Methods and systems for a transmission shift assembly

ABSTRACT

Various methods and systems are provided for a shift assembly for a vehicle transmission. In one example, a shift assembly for a transmission includes a first barrel cam including a first cam track; a second barrel cam arranged coaxially with the first barrel cam and including a second cam track; a first motor configured to drive the first barrel cam independent of the second barrel cam; and a second motor configured to drive the second barrel cam independent of the first barrel cam.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 16/983,896, entitled “METHODS AND SYSTEMS FOR ATRANSMISSION SHIFT ASSEMBLY”, and filed on Aug. 3, 2020. The entirecontents of the above-listed application are hereby incorporated byreference for all purposes.

TECHNICAL FIELD

Embodiments of the subject matter disclosed herein relate generally tomethods and systems for a shift assembly for a vehicle transmission.

BACKGROUND

Some vehicle transmissions include a shift mechanism configured totransition the transmission through a pre-determined gear engagementsequence. Each gear engagement of the sequence results in a particulargear ratio of the transmission, and the shift mechanism transitions thetransmission to each gear ratio in an ascending or descending order. Theascending order may include shifting from first gear, then to secondgear, then to third gear, and so forth, with the descending order beingthe reverse of the ascending order. The shift mechanism often includes abarrel cam to coordinate the shifting of the gears, where rotation ofthe barrel cam synchronizes movement of shift forks and synchronizerrings to disengage the currently selected gear and engage the next gearof the sequence in the ascending or descending order.

However, the inventors herein have recognized potential issues with suchsystems. As one example, degradation of the barrel cam and/or variationin vehicle operating conditions may result in undesired shift behavior,such as slower gear engagement and/or disengagement. Additionally,particular transitions of the gear engagement sequence occurring withhigher frequency during operation of the vehicle, such as the transitionbetween first gear and second gear, may result in different wearcharacteristics of the barrel cam relative to other transitions, whichmay further increase undesired shift behavior.

SUMMARY

In one example, the issues described above may be addressed by a shiftassembly for a transmission comprising: a first barrel cam including afirst cam track; a second barrel cam arranged coaxially with the firstbarrel cam and including a second cam track; a first motor configured todrive the first barrel cam independent of the second barrel cam; and asecond motor configured to drive the second barrel cam independent ofthe first barrel cam. In this way, the first barrel cam and secondbarrel cam may be driven to rotate independently of each other to adjustthe gear engagement of the transmission.

As one example, the first barrel cam and second barrel cam are rotatablycoupled independent of each other by a bushing. The first barrel cam andthe second barrel cam are supported by a first bearing and a secondbearing along a same rotational axis. The first motor and the secondmotor are controlled by an electronic controller. The first barrel cammay be driven in order to control engagement of a first plurality ofgears of the transmission, and the second barrel cam may be driven inorder to control at least one different gear of the transmission. As aresult, the barrel cams may be driven independently to provide tuning ofthe performance of the shift assembly for different gear engagementsand/or for different vehicle operating conditions such as oil type,temperature, driving habits, desired shift feel, etc.

It should be understood that the brief description above is provided tointroduce in simplified form a selection of concepts that are furtherdescribed in the detailed description. It is not meant to identify keyor essential features of the claimed subject matter, the scope of whichis defined uniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be better understood from reading thefollowing description of non-limiting embodiments, with reference to theattached drawings, wherein below:

FIG. 1 schematically shows a vehicle including a transmission and ashift assembly.

FIG. 2 shows a shift assembly for a transmission.

FIG. 3 shows an enlarged view of a motor of the shift assembly of FIG. 2.

FIG. 4 shows the shift assembly of FIG. 2 coupled to a plurality ofgears of a transmission.

FIGS. 5A-5F show a first barrel and a second barrel of the shiftassembly of FIG. 2 in different rotational positions.

FIG. 6 shows a flowchart depicting an example method for controllinggear engagement of a transmission via a shift assembly including a firstbarrel and a second barrel driven by different motors.

FIG. 7 shows a flowchart depicting a continuation of the method of FIG.6 during conditions in which a shift condition is present.

FIG. 8 shows a graph including plots illustrating various operatingparameters of a vehicle including a shift assembly having a first barreland a second barrel driven by different motors.

FIG. 9 shows a graph including plots illustrating shift thresholds of atransmission controlled via a shift assembly including a first barreland a second barrel driven by different motors.

DETAILED DESCRIPTION

The following disclosure relates to methods and systems for a shiftassembly of a vehicle transmission. A vehicle, such as the vehicle shownby FIG. 1 , includes a transmission and a shift assembly, such as theshift assembly shown by FIG. 2 . The shift assembly includes a splitbarrel mechanism, where a first barrel cam and a second barrel cam ofthe split barrel mechanism are arranged coaxially along a commonrotational axis and are spaced apart by a bushing. Each barrel cam mayrotate independently, and a controller adjusts rotation of the barrelcams in order to adjust the gear engagement of the transmission. Therotation of each barrel cam is controlled independently via respectiveindependently operated actuator systems, such as the actuator systemshown by FIG. 3 . Rotation of the barrel cams may occur responsive to ashift condition, as illustrated by the flowcharts of FIGS. 6-7 , withthe shift condition based on vehicle operating conditions, asillustrated by the graphs of FIGS. 8-9 . In some examples, thecontroller may concurrently rotate both of the first barrel cam andsecond barrel cam, and in some examples the controller may rotate onlyone of the first barrel cam or second barrel cam. The rotation of thebarrel cams adjusts the corresponding shift forks to various differentpositions, such as the positions shown by FIGS. 5A-5F. The shift forksslide along a shift rod parallel to the transmission input shaft toengage or disengage the gears of the transmission, such as thetransmission shown in FIG. 4 . In this way, the barrel cams of the shiftassembly may increase a shift performance of the transmission, and thecontroller may adjust each barrel cam independently based on vehicleoperating conditions in order to increase shift responsiveness and/orcontrol engagement of the gears in a non-sequential order.

Referring now to FIG. 1 , an example vehicle 100 is shown. In someexamples, vehicle 100 may be a hybrid vehicle configured to providetorque to one or more wheels from multiple sources, such as engine 101and electric motor 102. In other examples, vehicle 100 is configured toprovide torque to the one or more wheels via only one of engine 101 orelectric motor 102. In the example in which vehicle 100 is a hybridvehicle, operation of the vehicle 100 may be adjusted between variousdifferent modes in which torque is supplied to the one or more wheelsvia only the engine 101, via only the electric motor 102, or via acombination of the engine 101 and electric motor 102. Electric motor 102may be a motor/generator configured to provide torque output to the oneor more wheels and to generate electrical energy during operation of thevehicle 100 (e.g., via regenerative braking, as one example). Vehicle100 is provided as an example of a system including a shift assembly asdescribed herein. However, vehicle 100 is not intended to be limitingand in some examples the shift assembly may be included in vehicleshaving a different configuration (e.g., a different number and/orrelative configuration of wheels and/or other components).

The vehicle 100 may be powered by electric motor 102 and/or engine 101,which generates torque in a drive wheel 120 when one or more clutchesare engaged via a transmission 104 connected to a transmission inputshaft 106 and an output shaft 108. In FIG. 1 , the output shaft 108 is acountershaft that rotatably coupled to an input of a differential gearassembly 124, which may power one or more of a first drive wheel 120 anda second drive wheel 122 via drive axle 136. In other embodiments, theoutput shaft 108 may be coaxially aligned with the transmission inputshaft 106, and a countershaft may be used to provide torque applied tothe input shaft 106 to the output shaft 108 via a gear assembly of thetransmission. In still other embodiments, engine 101 and/or electricmotor 102, transmission 104, input shaft 106, and output shaft 108 maybe aligned perpendicular to the axles of vehicle 100, whereby thetransfer of torque from the output shaft to a drive wheel or drive axleis accomplished via the differential gear assembly 124 mounted on thedrive axle 136.

In some examples, the torque may be applied to only one drive wheel, orthe torque applied to the first drive wheel 120 and the second drivewheel 122 by the differential gear assembly 124 may be different (forexample, during cornering of the vehicle or operation on an unevenground surface), and in some conditions it may be approximately the same(for example, while driving the vehicle straight on a level groundsurface, without cornering). The vehicle 100 may also include one ormore free wheels, such as free wheels 126 and 128 mounted on free axle130. The free wheels may rotate as the vehicle is driven without beingdirectly propelled by the engine or electric motor (e.g., the engine andelectric motor do not apply torque directly to the axle coupled to thefree wheels). In other embodiments, additional free wheels may beincluded on free axle 130, and/or additional free axles may be includedin vehicle 100, each of which may include a plurality of wheels. Forexample, heavy trucks or buses may have additional front and/or rearaxles to distribute the weight of cargo, and each axle may include twowheels on each side. Still other embodiments may include a single freewheel, for example, in a motorcycle.

As shown in the illustrated example, the first drive wheel and thesecond drive wheel may be front wheels. In other embodiments, the firstdrive wheel and the second drive wheel may be rear wheels, and the frontwheels may be free wheels, or a transfer case (not depicted in FIG. 1 )may be used to power all the wheels on vehicle 100, for example, in thecase of 4-wheel drive vehicles or all-wheel-drive vehicles. The positionor number of drive wheels on vehicle 100 should not be construed aslimiting the scope of this disclosure.

Each of the wheels of the vehicle (e.g., wheel 120, wheel 122, wheel126, and wheel 128) may include a respective wheel speed sensor (whichmay be referred to herein as a vehicle speed sensor), such as wheelspeed sensors 113. The controller 110 may receive signals (e.g.,electronic signals) from the wheel speed sensors 113 and may determine aspeed of the vehicle based on the signals received from the wheel speedsensors 113.

In an embodiment, the transmission 104 may be an automated manualtransmission, whereby shifting is handled automatically by an electroniccontroller 110. Further, the transmission may be adjustable betweenvarious modes of operation. For example, an operator of the vehicle(e.g., a driver) may adjust the transmission between a manual mode inwhich gear selection is performed by the operator via an input device(e.g., a shift lever) and an automated mode in which the gear selectionis automatically determined by the controller based on vehicle operatingconditions (e.g., engine speed, vehicle speed, wheel torque, etc.). Thetransmission 104 is described in further detail below in reference toFIGS. 2-4 .

For automatic shifting, the electronic controller 110 may becommunicatively coupled to a shift assembly 112 that engages gears ofthe transmission 104 via a first barrel cam 160 and/or a second barrelcam 162. For example, the electronic controller 110 may command thefirst barrel cam 160 and/or the second barrel cam 162 to variousrotational positions in order to engage and/or disengage gears of thetransmission, similar to the examples described below with reference toFIGS. 2-9 . The shift assembly 112 may include actuator sensors fromwhich the electronic controller 110 may receive data used to controloperation of the shift assembly (e.g., to adjust a selected gear of thetransmission). The electronic controller 110 may also receive input fromother sensors of vehicle 100, such as wheel sensors, pedal positionsensors, temperature sensors, pressure sensors, speed sensors, throttlesensors, battery charge sensors, air-fuel ratio sensors, etc. Theelectronic controller 110 may send control signals to various actuatorscommunicatively coupled to electric motor 102, engine 101, and/or othercomponents of vehicle 100. The various actuators may include motors ofthe shift assembly 112 that engage the gears of transmission 104 bysliding synchronizer rings and cone clutches along the transmissionoutput shaft 108, via shift forks that slide along a selector shaft (notdepicted in FIG. 1 ). The various actuators may also include, forexample, various valves, throttles, fuel injectors, etc. The types ofsensors and actuators listed herein are for illustrative purposes andany type of sensors and/or actuators may be included without departingfrom the scope of this disclosure.

The shift assembly 112 may include an oil temperature sensor, such asthe oil temperature sensor 115 shown schematically by FIG. 1 . Thecontroller 110 may measure a temperature of oil within the transmission104 via signals (e.g., electronic signals) received by the controller110 via the oil temperature sensor 115 (e.g., the oil temperature sensor115 may be electrically coupled with the controller 110 and inelectronic communication with the controller 110). In some examples, theoil temperature sensor 115 may be arranged within a gearbox portion ofthe transmission 104 (e.g., a portion of the transmission 104 configuredto house the gears of the transmission 104). For example, the oiltemperature sensor 115 may be arranged proximate to the first barrel cam160, second barrel cam 162, one or more shift forks of the transmission,etc.

Electronic controller 110 may be a microcomputer, which may include amicroprocessor unit, input/output ports, and an electronic storagemedium for executable programs and calibration values. Electroniccontroller 110 may include non-transitory computer readable medium(memory) in which programming instructions are stored, and may beprogrammed with computer readable data representing instructionsexecutable to perform the methods described below, as well as othervariants that are anticipated but not specifically listed. Memory asreferenced herein may include volatile and non-volatile or removable andnon-removable media for a storage of electronic-formatted informationsuch as computer readable instructions or modules of computer readableinstructions, data, etc. Examples of computer memory may include, butare not limited to RAM, ROM, EEPROM, flash memory, or any other mediumwhich can be used to store the desired electronic format of informationand which can be accessed by the processor or processors or at least aportion of a computing device. The electronic controller 110 may beelectrically coupled to a battery 114 and a starter 116, which may beused to provide initial power to the controller and/or start the engine.The vehicle and engine may be controlled at least partially by thecontroller 110 and by input from a vehicle operator 150 via an inputdevice 152. In this example, input device 152 includes an acceleratorpedal and a pedal position sensor 154 for generating a proportionalpedal position signal.

In the example shown, the electronic controller 110 includes a learningmodule 111. Learning module 111 may be integrated with the memory of theelectronic controller 110. For example, learning module 111 may compriseone or more learning algorithms stored in the memory of the controller,such as one or more machine learning algorithms and/or deep neuralnetworks. The learning module 111 may adjust operation of the shiftassembly 112 based on vehicle operation data stored within the memory ofthe controller 110. As one example, the controller may measure and storedata acquired from various sensors of the vehicle (e.g., pedal positionsensor 154, oil temperature sensor 115, wheel speed sensors 113, etc.)through several cycles of vehicle operation (e.g., several ON/OFF cyclesof the engine, with each cycle spanning from an engine key-on event toan engine key-off event). The controller 110 may adjust operatingparameters of the vehicle based on the acquired data via the learningmodule 111. Adjusting the operating parameters may include adjusting arotation speed and/or rotation timing of the first barrel cam 160 and/orsecond barrel cam 162 (e.g., advancing and/or retarding a rotation ofthe barrel cams, increasing and/or decreasing the rotation speed of thebarrel cams, etc.), a shift timing of the transmission (e.g., viacontrol of the first barrel cam 160 and/or the second barrel cam 162),an amount of energization (e.g., duty cycle) and/or an energizationpolarity (e.g., change in voltage) of a first motor 164 configured todrive the first barrel cam 160 and/or a second motor 166 configured todrive the second barrel cam 162, etc.

As one example, the controller may adjust a relative rotation timing ofthe first barrel cam 160 and second barrel cam 162 (e.g., a rotationtiming of the first barrel cam 160 relative to the second barrel cam162, or vice versa) based on a predicted response rate of the firstbarrel cam 160 and/or second barrel cam 162, where the predictedresponse rate is determined via the learning module 111 based on thedata acquired through the several cycles of vehicle operation. For agiven barrel cam (e.g., the first barrel cam 160 or the second barrelcam 162), the predicted response rate of the given barrel cam may be aduration, as estimated by the controller 110 via the learning module 111based on the data acquired through the several cycles of vehicleoperation, from an initiation of a commanded rotation of the givenbarrel cam to a completion of the commanded rotation of the given barrelcam, where the completion of the commanded rotation immediately followsthe initiation of the commanded rotation (e.g., with no other commandedrotations therebetween). The predicted response rate may be estimated bythe controller based on the acquired data and/or as a function of one ormore vehicle operating parameters, such as transmission oil temperatureand/or the amount of energization of the motor configured to drive thegiven barrel cam (e.g., the first motor 164 configured to drive thefirst barrel cam 160 or the second motor 166 configured to drive thesecond barrel cam).

The electric motor 102 may be powered by a battery pack 118. Batterypack 118 may be an energy storage device configured to deliverelectrical power to various components of the electrical system of thevehicle 100 including supplying current to electric motor 102 coupled tofront wheels 120 and 122 and/or other powered wheels of the vehicle 100.The battery pack 118 may be electrically coupled with the electric motor102 and/or the electronic controller 110. The electronic controller 110may regulate the power supply provided by the battery pack 118 to theelectric motor 102 in order to increase or decrease the speed of thevehicle 100.

Engine 101 may be powered by fuel such as gasoline, diesel fuel, naturalgas, biofuels, or any other combustible fuel; and accordingly, thevehicle 100 may include a fuel tank connected to the engine 101 via afuel pump and intake system. The engine 101 and/or electric motor 102may be positioned on a chassis 134 in a variety of configurations. Forexample, engine 101 and electric motor 102 may be positioned proximateto each other, or engine 101 and electric motor may be positionedfurther apart from each other along the chassis 134.

Transmission 104, electric motor 102, and/or engine 101 may be cooled bya cooling system 132 (e.g., a radiator, fan, etc.) positioned on thechassis 134 proximate electric motor 102, transmission 104, and/orengine 101.

Referring now to FIG. 2 , shift assembly 200 shows an example gearactuator system featuring a split-barrel cam actuator. Shift assembly200 may be the same as or similar to shift assembly 112 of vehicle 100of FIG. 1 . In an embodiment, a first barrel cam 202 and a second barrelcam 204 are coaxially aligned between a front motor plate 206 at a firstside 250 and a clutch grounding plate assembly 208 at an opposing,second side 252.

The first barrel cam 202 and second barrel cam 204 may be secured viabearings 236 and 238, respectively, and coupled together by a bushing226 (e.g., thrust surface) positioned between the bearings 236 and 238,such that the first barrel cam 202 and the second barrel cam 204 mayrotate independently with respect to each other. Bushing 226 may includea protrusion 255 of the second barrel cam 204 shaped to seat within arecess 257 of the first barrel cam 202. The second barrel cam 204 mayrotate independently of the first barrel cam 202, and as the secondbarrel cam 204 rotates, the protrusion 255 of the second barrel cam 204may rotate within the recess 257 of the first barrel cam 202. The firstbarrel cam 202 and second barrel cam 204 may each rotate bidirectionallyalong rotational axis 251. For example, first barrel cam 202 may rotatea clockwise direction around the rotational axis 251 while second barrelcam 204 rotates in a counterclockwise direction around the rotationalaxis 251, or first barrel cam 202 may rotate in a counterclockwisedirection while second barrel cam 204 rotates in a clockwise direction,or both barrel cams may rotate in the same direction, either clockwiseor counterclockwise. A controller (e.g., similar to the electroniccontroller 110 shown by FIG. 1 and described above) in electroniccommunication with an actuator of the first barrel cam 202 and anactuator of the second barrel cam 204 may command the first barrel cam202 to rotate in the clockwise or counterclockwise direction. Althoughthe first barrel cam 202 and second barrel cam 204 are arranged alongthe same rotational axis, the controller may command the second barrelcam 204 to rotate in the clockwise or counterclockwise direction,independently from the rotation of the first barrel cam 202. Forexample, the controller may command only the first barrel cam 202 torotate, the controller may command only the second barrel cam 204 torotate, or the controller may rotate the first barrel cam 202 and secondbarrel cam 204 concurrently.

The outer perimeter of the first barrel cam 202 and the outer perimeterof the second barrel cam 204 includes a plurality of detent grooves 234.The detent grooves 234 on the first barrel cam 202 (not depicted in FIG.2 ) and the second barrel cam 204 provide for the first barrel cam 202and the second barrel cam 204 to rotate in discrete angular incrementsto ensure precision in the rotation. As one example, each detent grooveformed in the first barrel cam 202 and the second barrel cam 204 may bespaced apart from each adjacent detent groove by 5° around the outerperimeter of the second barrel cam 204, such that the second barrel camincludes 72 detent grooves (e.g., spanning 360° of the outer perimeter),whereby the detent grooves provide for the first barrel cam 202 and thesecond barrel cam 204 to rotate in increments of 5° (e.g., 30°, 35°,40°, etc.). In other embodiments, the detent grooves of the first barrelcam 202 and second barrel cam 204 may be in a different arrangement. Forexample, each detent groove formed in the first barrel cam 202 and/orthe second barrel cam 204 may be arranged in a rotational position ofthe first barrel cam 202 and/or the second barrel cam 204 thatcorresponds to the engagement of a gear of the transmission. Thus, clearand discrete rotational positions of the first barrel cam 202 and thesecond barrel cam 204 may be communicated to a drive controller such aselectronic controller 110 of vehicle 100 of FIG. 1 , as described infurther detail below with respect to FIG. 3 .

The first barrel cam 202 and the second barrel cam 204 are shown coupledto an actuator motor assembly 210 that includes a first actuator motor212 and a second actuator motor 214. The first barrel cam 202 is coupledto the first actuator motor 212 via a first actuator gear assembly 216,and the second barrel cam 204 is coupled to the second actuator motor214 via a second actuator gear assembly 218. The first actuator gearassembly 216 and the second actuator gear assembly 218 may couple to thefirst barrel cam 202 and the second barrel cam 204 proximate to thecentral location of the bushing 226, such that the first barrel cam 202and the second barrel cam 204 may be independently rotated eitherclockwise or counterclockwise via force applied by the respectiveactuator gear assembly at approximately the center of the barrel cam.The first actuator gear assembly 216 and the second actuator gearassembly 218 may be arranged along a shared axis 260, where the axis 260is parallel to rotational axis 251 of the first barrel cam 202 andsecond barrel cam 204. The central positioning of first actuator motor212 and second actuator motor 214 and arrangement of the first actuatorgear assembly 216 and the second actuator gear assembly 218 along theaxis 260 may result in a reduced amount of space occupied by the motorsand gear assemblies and a more compact arrangement of transmissioncomponents. For example, the configuration described above may result ina reduced packaging space of the shift assembly 200 relative to aconfiguration in which the first actuator motor 212 and the secondactuator motor 214 are arranged at either ends of the barrel cam. In oneexample, actuator motor assembly 210 may be bolted to a gearbox housingportion 220, such that the actuator motor assembly 210 lies outside thegearbox while the barrel cam lies inside the gearbox proximate atransmission, and where the actuator motor assembly 210 is coupled tothe first barrel cam 202 and second barrel cam 204 via actuator gearassemblies 216 and 218, respectively. The actuator gear assemblies 216and 218 may be referred to herein as reduction gearings and/or reductiongearing assemblies.

In the example shown, an oil temperature sensor 221 is arranged withinthe gearbox housing portion 220, proximate to the first actuator gearassembly 216, the second actuator gear assembly 218, the first actuatormotor 212, and the second actuator motor 214. The oil temperature sensor221 may be electrically coupled to a controller of the vehicle includingthe shift assembly 200 (e.g., the controller 110 described above withreference to FIG. 1 ), and the controller may determine the temperatureof oil within the transmission (e.g., within the gearbox housing portion220) via signals (e.g., electronic signals) transmitted to thecontroller by the oil temperature sensor 221.

First barrel cam 202 and second barrel cam 204 may have a first camtrack 228 and a second cam track 230, respectively, cut on them to serveas shift fork position grooves, by which a first shift fork 222 and asecond shift fork 224, respectively, may be moved along a gear selectorshaft 232 (e.g., along axis 253, parallel to axis 251 and axis 260). Thefirst shift fork 222 and the second shift fork 224 may be coupled withthe first barrel cam 202 and a second barrel cam 204 via a first shiftfork following pin 246 and a second shift fork following pin 248,respectively, whereby the first shift fork following pin 246 slidesalong the first cam track 228 and the second shift fork following pin248 slides along the second cam track 230. Thus, as first barrel cam 202rotates, the first shift fork following pin 246 follows the first camtrack 228, causing the first shift fork 222 to slide in one direction oranother along the gear selector shaft 232 in parallel with the axis ofthe barrel cam, depending on the position of the first cam track 228 atthe point where it meets the first shift fork following pin 246. Asfirst shift fork 222 slides along the gear selector shaft 232, it slidesa first clutch collar 240 along a transmission output shaft 244 of atransmission. The transmission may be the same as or similar totransmission 104 of vehicle 100, and the output shaft 244 may be thesame as or similar to output shaft 108 of vehicle 100.

Similarly, as second barrel cam 204 rotates, the second shift forkfollowing pin 248 follows the second cam track 230, causing the secondshift fork 224 to slide in one direction or another along the gearselector shaft 232 in parallel with the axis of the barrel cam,depending on the position of the second cam track 230 at the point whereit meets the second shift fork following pin 248. As second shift fork224 slides along the gear selector shaft 232, it slides a second clutchcollar 242 along transmission output shaft 428 of the transmission. Theinteraction between the first shift fork 222 and the second shift fork224 and the transmission is discussed in further detail below inrelation to FIG. 4 .

The shift assembly 200 may be configured such that one or more gears ofa transmission (e.g., similar to the transmission 104 shown by FIG. 1and described above) may be engaged or disengaged via the first barrelcam 202, and one or more different gears of the transmission may beengaged or disengaged via the second barrel cam 204. For example,engagement or disengagement of the third gear of the transmission may becontrolled by rotation of the second barrel cam 204, while engagement ordisengagement of the first gear and second gear may be controlled byrotation of the first barrel cam 202. During conditions in which thegear engagement is shifted from second gear to third gear, a controller(such as the electronic controller 110 of vehicle 100 of FIG. 1 ) mayrotate the third gear independently relative to rotation of the secondgear. The controller may also independently control the rotational speedof each of the first barrel cam 202 and the second barrel cam 204 inorder to increase shift performance. For example, the controller mayinitiate rotation of the second barrel cam 204 prior to initiatingrotation of the first barrel cam 202, or may rotate the second barrelcam 204 at a different rotational speed than the first barrel cam 202,in order to reduce a transition time from engagement of the second gearto engagement of the third gear. This enables the shifting of gears tobe adjusted according to one or more conditions or vehicle operatingparameters, in order to vary the dynamic friction overlap of off-goingand on-coming elements (e.g., gear phasing). Gear phasing is discussedin further detail below with reference to FIGS. 6-7 .

In addition to increasing shift performance, the use of a split-barrelcam in shift assembly 200 has additional benefits. Because the firstbarrel cam 202 is driven by a first actuator motor 212 (which may bereferred to herein as a first motor and/or first power source), thesecond barrel cam 204 is driven by a second actuator motor 214 (whichmay be referred to herein as a second motor and/or second power source),and the first barrel cam 202 and second barrel cam 204 are rotatableindependent of each other, a size of the first barrel cam 202 and thesecond barrel cam 204 may be reduced relative to configurations thatinclude a single barrel cam. For example, some conventional systems areconfigured to control engagement and disengagement of each gear of thetransmission via a larger, single barrel cam. However, by configuringthe shift assembly 200 to include the first barrel cam 202 and thesecond barrel cam 204 as described herein, a rotational inertia of thefirst barrel cam 202 and a rotational inertia of the second barrel cam204 may be decreased relative to a rotational inertia of theconventional, single barrel cam. Further, because the first barrel cam202 and second barrel cam 204 are rotated via the first actuator motor212 and the second actuator motor 214 respectively, a load on each ofthe first actuator motor 212 and the second actuator motor 214 may bereduced relative to configurations that include load applied to a singlemotor, and a size of each of the first actuator motor 212 and the secondactuator motor 214 may be reduced. The reduced load applied to the firstactuator motor 212 and the second actuator motor 214 and the reducedrotational inertia of the first barrel cam 202 and the second barrel cam204 may additionally reduce a likelihood of degradation of the firstactuator motor 212, the second actuator motor 214, the first barrel cam202, and the second barrel cam 204, and other components of the shiftassembly 200.

Additionally, in the configuration described herein, the first actuatormotor 212 and the second actuator motor 214 may apply force to the firstbarrel cam 202 and second barrel cam 204 proximate to a location atwhich the first barrel cam 202 and second barrel cam 204 are rotatablycoupled to each other (e.g., coupled such that the first barrel cam 202and second barrel cam 204 may rotate relative to each other), such as atopposing sides of a bushing arranged between the first barrel cam 202and second barrel cam 204. By applying force to the first barrel cam 202and second barrel cam 204 in this way, a reduced amount of force may beapplied in order to initiate rotation of the first barrel cam 202 andsecond barrel cam 204, control of the rotation of the first barrel cam202 and second barrel cam 204 may be increased, and a likelihood ofdegradation of the first barrel cam 202 and second barrel cam 204 may bedecreased.

Another benefit of the independent operation of first barrel cam 202 andsecond barrel cam 204 is that the controller may be configured to switchbetween various control modes of the shift assembly 200 for differentuses (e.g., different driving conditions, different user preferences,etc.). For example, an operator of a vehicle (e.g., vehicle 100 of FIG.1 ) may input a selection of a desired operating mode via a user inputdevice (e.g., a lever, button, touchscreen, etc.), and the controllermay adjust operation of the shift assembly 200 according to the selectedoperating mode. One example mode may include a shift timing configuredto provide smoother shifting under heavy loads, while another mode maybe configured to provide increased shift performance for high vehiclespeed applications.

The independent operation of the two barrel cams also enables gearshifting in a non-sequential order (e.g., gear skipping). For example,in some conditions, shifting efficiency and/or speed may be increased byshifting directly from one gear to another in a non-sequential order(e.g., shifting from first gear directly to third gear, or vice versa,without engaging the second gear during the shift between first gear andthird gear). Such conditions may include operating the vehicle with thefirst gear of the transmission engaged and increasing a speed of thevehicle above a threshold speed while the first gear is still engaged.Responsive to the speed of the vehicle increasing above the thresholdspeed while the first gear is engaged, the controller may adjustoperation of the shift assembly to shift directly from engagement of thefirst gear to engagement of the third gear, without engaging the secondgear. The non-sequential shifting order may increase vehicle performanceand/or efficiency. Gear skipping is discussed in further detail belowwith reference to FIGS. 6-7 .

It should be further appreciated that because each of the first barrelcam 202 and second barrel cam 204 may be rotated independently, duringsome conditions the controller may rotate the first barrel cam 202 andsecond barrel cam 204 in order to engage multiple gears of thetransmission at once in order to lock an output of the transmission. Forexample, the controller may concurrently engage the first gear via thefirst barrel cam 202 and the third gear via the second barrel cam 204 tolock the transmission while the vehicle is parked. In this way, theposition of the vehicle may be maintained by the transmission to reducea likelihood of undesired movement of the vehicle.

Referring now to FIG. 3 , an enlarged view a portion of the actuatormotor assembly 210 that includes the first actuator motor 212 is shown.While the enlarged view shows components relating to first actuatormotor 212, it should be appreciated that similar components may be foundand similar actions may be triggered with respect to second actuatormotor 214, also housed within actuator motor assembly 210. Therefore,each of the components mentioned below may have a counterpart relatingto second actuator gear assembly 218 and second barrel cam 204.

The first actuator motor 212 may be attached to the gearbox housingportion 220 via motor bearings 302 and 304, such that the first actuatorgear assembly 216 may be driven to rotate the first barrel cam 202 inorder to engage a selected gear. A position sensor 306 is shownproximate the first actuator gear assembly 216, bolted to the housing ofthe actuator motor assembly 210 via a position sensor retaining bolt308, at a location where position sensor retaining bolt 308 does notobstruct the movement of the first actuator gear assembly 216. Theposition sensor 306 is depicted as electronically coupled to thecontroller, such that the rotational position of the first actuator gearassembly 216 (and the first barrel cam 202) may be communicated to thecontroller in order to determine, in conjunction with signals (e.g.,electronic signals) from one or more of a plurality of sensors (e.g.,engine speed sensors, vehicle speed sensors, wheel torque sensors,throttle position sensors, etc.), whether to shift gears and what gearto shift into.

For example, a vehicle such as vehicle 100 with a shift assembly 200 maybe driving with the transmission engaged in first gear. As explained infurther detail in relation to FIG. 4 , first gear may correspond to afirst position of the first shift fork 222 on the gear selector shaft232. The position of the first shift fork 222 on the gear selector shaft232 is based on the position of the first shift fork following pin 246on the first cam track 228, such that as the first barrel cam 202rotates, the first shift fork following pin 246 slides the first shiftfork 222 left or right depending on rotational position of first barrelcam 202. Thus, first gear corresponds to a specific rotational positionof the first barrel cam 202 around its axis. As mentioned earlier, therotational position of the first barrel cam 202 is divided into discretemeasurements via the detent grooves 234, whereby the rotational positionof first barrel cam 202 may correspond to a specific gear position(e.g., a position at which a specific gear of the transmission isengaged) to ensure accurate rotational positioning for full gearengagement.

As vehicle 100 speeds up, electronic controller 110 may receiveindications of vehicle speed from sensors on vehicle 100 (e.g., pedalposition sensors, throttle sensors, wheel sensors, etc.). Additionally,electronic controller 110 may receive from position sensor 306 anindication that first barrel cam 202 has been rotated to a positioncorresponding to first gear. When the speed of vehicle 100 exceeds athreshold value for first gear (e.g., 10 miles per hour), electroniccontroller 110 may signal to the first actuator motor 212 to engage thefirst actuator gear assembly 216 in order to rotate first barrel cam 202to a rotational position corresponding to second gear. As first barrelcam 202 rotates, the point of contact between the first shift forkfollowing pin 246 and the first cam track 228 may shift horizontallyalong the selector shaft 232, dragging the first shift fork 222 througha neutral position to a position where first shift fork 222 engagessecond gear of the transmission 104 of vehicle 100. When first barrelcam 202 has rotated to the rotational position corresponding to secondgear, position sensor 306 may indicate to electronic controller 110 thatvehicle 100 is in second gear. It should be appreciated that as thetransition between first and second gears is accomplished via the firstbarrel cam 202, without the involvement of the second barrel cam 204,the second barrel cam 204 may remain in a neutral position during thetransition between first and second gears, whereby the second shift fork224 is positioned such that gears of the transmission are not engaged bysecond shift fork 224. Operating the vehicle with the first barrel cam202 and second barrel cam 204 in the neutral position may be referred toherein as a neutral mode of the vehicle, while operating the vehiclewith the gears of the transmission engaged (e.g., with only the firstgear engaged, with only the second gear engaged, or with only the thirdgear engaged) may be referred to herein as a drive mode of the vehicle.

Similarly, when electronic controller 110 receives signals from sensorssuch as pedal position sensors, throttle sensors, wheel sensors, etc.,that the speed of vehicle 100 has exceeded a threshold value for secondgear (e.g., 20 miles per hour), electronic controller 110 may signal tothe first actuator motor 212 to engage the first actuator gear assembly216 in order to rotate first barrel cam 202 to a rotational positioncorresponding to neutral. As first barrel cam 202 rotates, the linearposition of first cam track 228 at the point of contact with first shiftfork following pin 246 may shift along a selector shaft 232, draggingthe first shift fork 222, via the first shift fork following pin 246, tofirst shift fork 222's neutral position. Independently, the electroniccontroller 110 may signal to the second actuator motor 214 to engage thesecond actuator gear assembly 218 to rotate second barrel cam 204 to arotational position corresponding to third gear. As the second barrelcam 204 rotates, the linear position of the second cam track 230 at thepoint of contact with the second shift fork following pin 248 may shiftalong the selector shaft 232, dragging the second shift fork 224, viathe second shift fork following pin 248, to a position where the secondshift fork 224 engages third gear of the transmission 104. When thefirst barrel cam 202 has rotated to the rotational positioncorresponding to neutral and the second barrel cam 204 has rotated tothe rotational position corresponding to third gear, position sensor 306may indicate to electronic controller 110 that vehicle 100 is in thirdgear. Engagement and disengagement of the gears of the transmission 104via the shift forks is described in further detail below with respect toFIG. 4 .

The split-barrel cam actuator disclosed herein provides independentoperation of the first barrel cam 202 and the second barrel cam 204. Inthis configuration, the transmission may shift directly between thevarious gears on demand, providing greater shift control flexibility andcalibration. Conventional systems include transmission gears that areconfigured to engage in a pre-determined order. However, the system ofthe present disclosure may initiate a transition to engage one gear(e.g., third gear) via second shift fork 224 prior to fully disengaginga previous gear (e.g., second gear) via first shift fork 222, in orderto facilitate more rapid and efficient gear shifting under certainconditions.

For example, while driving in second gear, if vehicle 100 achieves avehicle speed that exceeds a threshold for shifting into third gear(e.g., 20 miles an hour), the electronic controller 110 may coordinatethe disengagement of second gear via the first actuator motor 212 withthe engagement of third gear via the second actuator motor 214, suchthat first barrel cam 202 is rotated to disengage from second gear andsecond barrel cam 204 is rotated to engage in third gear slightly priorto full disengagement from second (referred to herein as gear phasing).Altering the speed of each barrel cam provides for for independentcontrol behavior, which may increase shifting efficiency. In someconditions, gear phasing as described above may provide increased fuelefficiency and increased driver comfort (e.g., due to a decreasedlikelihood of abrupt shift changes). In some examples, the controllermay utilize one or more learning algorithms to adjust shift operationbased on previous operating conditions, and the adjusted shift operationmay reduce a likelihood of transmission degradation (e.g., reducetransmission wear).

Further, while driving in first gear, if a shift condition is met forshifting into third gear, the electronic controller 110 may activate thefirst actuator motor 212 and the second actuator motor 214 concurrentlyin order to rotate first barrel cam 202 and second barrel cam 204 todisengage first gear and engage third gear directly, transitioningdirectly from first gear to third gear and skipping engagement of thesecond gear. For example, while driving in first gear, a shift conditionmay be met for shifting into second gear if vehicle 100 achieves a speedabove a threshold speed (e.g., 20 miles an hour) and the averageacceleration of vehicle 100 over a duration prior to reaching thethreshold speed (e.g., the second prior to reaching the threshold speed)is below a threshold acceleration (e.g., 2.5 m/s2 or 6 mph/s).Alternatively, a shift condition may be met for shifting into third gearif vehicle 100 achieves a speed above the threshold speed and theaverage acceleration of vehicle 100 is above the threshold acceleration.The decision of whether to shift from first gear to second gear or toshift from first gear to third gear while skipping second gear may bebased on other or additional factors. For example, commanded gearskipping during an upshift may be performed if the weight of the vehicleload is below a threshold value, and the acceleration is above athreshold value, and the controller determines that the resulting gearcan handle the load. As another example, commanded gear skipping duringan upshift (e.g., shifting directly from engagement of the first gear toengagement of the third gear) may be performed responsive to pedal liftoff and/or during conditions of low throttle (e.g., relatively lowamount of throttle opening) while operating in a fuel economy mode ofthe vehicle (e.g., a mode configured to control shift operation toreduce a fuel consumption of the vehicle). Commanded gear skippingduring a downshift may be performed during wide open throttle (WOT) toachieve increased wheel torque with reduced shift interruption, orduring a transition from operating the vehicle at a relatively highvehicle speed condition to operating the vehicle in a stationaryposition condition (e.g., a parked position). The commanded gearskipping during the downshift may occur as the vehicle speed decreasesfrom the relatively high vehicle speed to the stopped condition. In somecases, a threshold speed for shifting into a gear of the transmissionmay be different from a threshold speed for shifting out of the samegear of the transmission, for example, to reduce a likelihood of asituation in which alternating shift conditions are repeatedly met, suchas when the speed of vehicle 100 hovers around a threshold speed forshifting gears.

Further still, responsive to user input, such as pushing abutton/switch, touching a touchscreen, or otherwise indicating that aparking condition is desired, independent actuation of first barrel cam202 and second barrel cam 204 may be utilized to engage both first andthird gears concurrently while vehicle 100 is not moving in order tolock the geartrain to the stationary housing. In this configuration, therotational position of the wheels of the vehicle may be maintained bythe transmission such that the wheels do not rotate. As one example,this configuration may be utilized for parking the vehicle (e.g., tosupplement, or substitute for, a chassis parking brake).

Referring now to FIG. 4 , transmission engagement diagram 400 shows howthe split-barrel cam actuator system exemplified in FIGS. 2 and 3engages the gears of a transmission such as transmission 104 of vehicle100 of FIG. 1 . An electric motor 402 may be operably coupled to shiftassembly 200 via transmission input shaft 404. Electric motor 402 may bethe same as or similar to electric motor 102 of vehicle 100 of FIG. 1 ,or, as described with reference to FIG. 1 , in other embodimentselectric motor 402 may be replaced by an internal combustion engine, ortransmission input shaft 404 may be driven by a combination of powergenerated by an electric motor and power generated by an internalcombustion engine, for example in a hybrid vehicle. For the purposes ofthis disclosure, transmission input shaft 404 may be powered by variouspower sources, whether electric or utilizing a fuel such as gasoline,natural gas, diesel, etc.

As described below, as gears are shifted, the rotation of thetransmission input shaft 404 is transmitted to transmission output shaft428, which is rotatably coupled to a differential gear assembly 430,which in turn rotates a drive wheel 406. The transmission output shaft428, the differential gear assembly 430, and the drive wheel 406 may bethe same as or similar to the output shaft 108, differential gearassembly 124, and drive wheel 120 of vehicle 100 of FIG. 1 . Thetransmission output shaft 428 may also be the same as or similar to theoutput shaft 244 of FIG. 2 .

In an embodiment, a first gear 410, a second gear 412, and a third gear414 rotate around the transmission output shaft 428. In otherembodiments, additional gears may be included (e.g., fourth gear, fifthgear, reverse gear, etc.). For example, an embodiment with four gearsmay include a fourth gear that is engaged by second shift fork 224 ofthe shift assembly 200 described above, positioned on the transmissionoutput shaft 428 on the opposite side of the second shift fork 224 asthe third gear 414. Additionally or alternatively, first barrel cam 202and/or second barrel cam 204 may be extended in length to includeadditional cam tracks that drive corresponding additional shift forks,such that additional gears may be added on the transmission output shaft428. For example, second barrel cam 204 may be extended to include athird cam track, that drives a third shift fork to engage a fifth gearwith a smaller gear ratio than fourth gear (e.g., overdrive). As aresult, the split-barrel actuator mechanism disclosed herein may be usedwith a different number of gears.

FIG. 4 depicts an input shaft 404 positioned in parallel with andproximate the transmission output shaft 428, around which a first inputshaft gear 422, a second input shaft gear 424, and the third input shaftgear 426 rotate, which are rotatably coupled to the first gear 410, thesecond gear 412, and the third gear 414, respectively. Via the inputshaft 404, the torque generated on the transmission output shaft 428 byelectric motor 402 is transferred to the differential gear assembly 430and the drive wheel 406 in accordance with a particular gear ratio forthe relevant gear. As an example, in an embodiment, the first inputshaft gear 422 is rotatably coupled to the first gear 410 at a gearratio of 3.666, the second input shaft gear 424 is rotatably coupled tothe second gear 412 at a gear ratio of 2.047, and the third input shaftgear 426 is rotatably coupled to the third gear 414 at a gear ratio of1.258. Thus, when the vehicle is in first gear, the first input shaftgear 422 engages with the first gear 410 such that the transmissioninput shaft 404 completes 3.666 rotations in order for the transmissionoutput shaft 428 to complete a single rotation. When the vehicle is insecond gear, the second input shaft gear 424 engages with the secondgear 412 such that the transmission input shaft 404 completes 2.047rotations in order for the transmission output shaft 428 to complete asingle rotation. When the vehicle is in third gear, the third inputshaft gear 426 engages with the third gear 414 such that thetransmission input shaft 404 completes 1.258 rotations in order for thetransmission output shaft 428 to complete a single rotation. The gearratios described herein are for illustrative purposes, and other gearratios may be substituted without departing from the scope of thisdisclosure.

Gears 410, 412, and 414 are engaged by the shift assembly 200 via firstshift fork 222 and second shift fork 224. As described above, firstactuator motor 212 and second actuator motor 214 are activated by acontroller (e.g., the electronic controller 110 of vehicle 100) in orderto engage the first barrel cam 202 and the second barrel cam 204 viafirst actuator gear assembly 216 and second actuator gear assembly 218,respectively. The rotational position of first barrel cam 202 alignsfirst shift fork 222 along gear selector shaft 232 according to theposition of first shift fork cam following pin 246 within first camtrack 228. Similarly, the rotational position of second barrel cam 204aligns second shift fork 224 along gear selector shaft 232 according tothe position of second shift fork cam following pin 248 within secondcam track 230. Thus, the rotational positions of first barrel cam 202and second barrel cam 204 determine the positions of the first clutchcollar 240 and the second clutch collar 242 attached to the first shiftfork 222 and second shift fork 224 at the location of the transmissionoutput shaft 428.

The first clutch collar 240 and the second clutch collar 242 rotatefreely during the engagement and disengagement of gears. First clutchcollar 240 and second clutch collar 242 are moved horizontally either tothe left or to the right along transmission output shaft 428 to engageand disengage gears in accordance with the movement of first shift fork222 and second shift fork 224, respectively, as described earlier.Clutch collars 240 and 242 engage the gears positioned on the right orto the left of clutch collars 240 and 242 via synchronizer ring/coneclutch assemblies 416, 418, and 420, whereby a clutch collar engages therelevant gear by sliding to connect the teeth of a hub fixed to thetransmission output shaft 428 with similarly sized teeth on the relevantgear.

For example, in the embodiment depicted in FIG. 4 , to engage firstgear, when the first shift fork 222 is moved to the left via therotation of first barrel cam 202 as described above, first clutch collar240 slides synchronizer ring/cone clutch assembly 416 from the neutralposition (e.g., in which no gears are engaged) to the left to engagefirst gear 410. First gear 410 engages first input shaft gear 422, whichis rotated by the motor 402 via the input shaft 404, to turn the drivewheel 406. To disengage first gear and enter into second gear, the firstshift fork 222 is moved to the right via the rotation of first barrelcam 202 in the opposite direction, and first clutch collar 240 slidessynchronizer ring/cone clutch assembly 416 into the neutral position tothe right to disengage first gear 410. Further rotation of the firstbarrel cam 202 slides first shift fork 222 to the right, whereby firstclutch collar 240 slides synchronizer ring/cone clutch assembly 416 tothe right to engage second gear 412. Second gear 412 engages secondinput shaft gear 424, which is rotated by the motor 402 via the inputshaft 404, to turn the drive wheel 406. To disengage second gear andenter into third gear, the first shift fork 222 is moved to the left viathe rotation of first barrel cam 202 in the opposite direction, andfirst clutch collar 240 slides synchronizer ring/cone clutch assembly416 into the neutral position to the left to disengage second gear 412.Rotation of the second barrel cam 204 slides second shift fork 224 tothe left, whereby second clutch collar 242 slides synchronizer ring/coneclutch assembly 418 to the left to engage third gear 414. Third gear 414engages third input shaft gear 426, which is rotated by the motor 402via the input shaft 404, to turn the drive wheel 406.

As mentioned above, it should be appreciated that because the rotationof first barrel cam 202 and the rotation of second barrel cam 204 can beactuated independently via first actuator motor 212 and/or secondactuator motor 214, when disengaging second gear and entering into thirdgear, third gear can be “phased-in” by timing the rotation of secondbarrel cam 204 to initiate the transition of engagement of the thirdgear slightly before second gear is fully disengaged, thus increasingthe speed and efficiency of shifting between second and third gears.Additionally, the independent actuation of first barrel cam 202 andsecond barrel cam 204 may provide for a drive controller such aselectronic controller 110 of vehicle 100 to rotate first barrel cam 202in order to move first shift fork 222 to disengage from first gear 410,and rotate second barrel cam 204 in order to move second shift fork 224to engage third gear 414, thus skipping second gear. For example, ifvehicle speed passes a first threshold speed for engaging second gear,and the controller detects acceleration above a threshold acceleration,the controller may determine that it would be more efficient not toengage second gear, but rather to wait until a second threshold speed isreached for engaging third gear. As mentioned above, first gear 410 andthird gear 414 may also be engaged concurrently while the vehicle is notin motion in order to prevent the wheels from moving (e.g., to adjustthe vehicle to a parked configuration).

Referring collectively to FIGS. 5A-5F, various rotational positions of afirst barrel cam 500 and a second barrel cam 502 are shown. The firstbarrel cam 500 and second barrel cam 502 are in a coaxial arrangement(e.g., arranged along a shared rotational axis 550) spaced apart bybushing 526 and may be similar to, or the same as, the first barrel cam202 and second barrel cam 204, respectively, described above withreference to FIGS. 2-4 . The first barrel cam 500 and second barrel cam502 may be commanded to the rotational positions shown by FIGS. 5A-5Fvia a controller of a vehicle, such as the electronic controller 110 ofvehicle 100 shown by FIG. 1 and described above. For example, thecontroller may command the first barrel cam 500 to rotate in a firstdirection (e.g., clockwise) or a second direction (e.g.,counter-clockwise) via a first motor (e.g., first actuator motor 212shown by FIG. 2 and described above), and/or the controller may commandthe second barrel cam 502 to rotate in the first direction or seconddirection via a second motor (e.g., second actuator motor 214 shown byFIG. 2 and described above). The first barrel cam 500 is rotatableindependently from the second barrel cam 502 such that the first barrelcam 500 may be rotated without rotating the second barrel cam 502, andvice versa.

The different rotational positions of the first barrel cam 500 andsecond barrel cam 502 correspond to different gear engagements of thetransmission (e.g., similar to transmission 104 shown by FIG. 1 anddescribed above). In particular, in the configuration shown by FIG. 5A,the gears of the transmission are not engaged. In the configurationshown by FIG. 5B, the first barrel cam 500 is rotated from the neutralposition shown by FIG. 5A to a position in which the first gear (e.g.,first gear of the gear sequence of the transmission) of the transmissionis engaged. In the configuration shown by FIG. 5C, the first barrel cam500 is further rotated from the position shown by FIG. 5B to a positionin which the second gear (e.g., second gear of the gear sequence) of thetransmission is engaged. In the configuration shown by FIG. 5D, thefirst barrel cam 500 is rotated to the neutral position, and the secondbarrel cam 502 is rotated from the neutral position shown by FIGS. 5A-5Cto a position in which the third gear of the transmission (e.g., thirdgear of the gear sequence of the transmission) is engaged. In theconfiguration shown by FIG. 5E, the first barrel cam 500 and secondbarrel cam 502 are commanded to positions corresponding to engagement ofboth of the first gear and the third gear of the transmission (e.g., forparking of the vehicle). In the configuration shown by FIG. 5F, thefirst barrel cam 500 and second barrel cam 502 are each in atransitional position corresponding to adjustment from engagement of thesecond gear to engagement of the third gear. Gear engagement, asdescribed herein, refers to engagement of the gears of the transmissionfor adjusting the output of the transmission (e.g., to propel thevehicle). For example, during conditions in which the first gear isengaged, a gear ratio of the transmission may higher (e.g.,approximately 3.6), during conditions in which the second gear isengaged, the gear ratio may be lower (e.g., approximately 2.0), andduring conditions in which the third gear is engaged, the gear ratio maybe lower (e.g., approximately 1.2). However, during conditions in whichboth of the first gear and the third gear of the transmission areengaged (e.g., for maintaining the position of the vehicle while thevehicle is parked), the transmission does not provide output to thewheels of the vehicle (e.g., the output of the transmission is locked).

FIG. 5A shows the first barrel cam 500 and second barrel cam 502 each ina neutral rotational position. In this configuration, first shift forkfollowing pin 512 is seated within a straight section 520 of cam track504 of the first barrel cam 500, and second shift fork following pin 514is seated within a straight section 522 of cam track 506 of the secondbarrel cam 502. The first shift fork following pin 512, cam track 504,second shift fork following pin 514, and cam track 506 may be similarto, or the same as, the first shift fork following pin 246, first camtrack 228, second shift fork following pin 248, and second cam track230, respectively, described above with reference to FIGS. 2-4 .

The cam track 504 of first barrel cam 500 includes straight section 520,a first angled section 516, and a second angled section 524. The camtrack 506 of second barrel cam 502 includes straight section 522 and anangled section 518. FIGS. 5A-5F each show a flattened view of the firstbarrel cam 500 and second barrel cam 502, and it should be appreciatedthat the first barrel cam 500 and second barrel cam 502 each have acylindrical shape, similar to the example of first barrel cam 202 andsecond barrel cam 204 described above. The first barrel cam 500 andsecond barrel cam 502 are shown in the flattened views for ease ofillustration, with the degree markers shown along the sides of the firstbarrel cam 500 and second barrel cam 502 included to indicate portionsalong the cylindrical perimeter of the first barrel cam 500 and secondbarrel cam 502. For example, a first portion of first barrel cam 500 isindicated by the marker labeled 60 degrees and a second portion of thefirst barrel cam 500 is indicated by the marker labeled 120 degrees,with the second portion being offset from the first portion by 60degrees around the rotational axis 550 of the first barrel cam 500(e.g., similar to rotational axis 251 shown by FIG. 2 and describedabove). The straight section 520 extends along the perimeter of thefirst barrel cam 500 in a relatively straight direction along theperimeter of the first barrel cam 500 (e.g., a direction around therotational axis 550 of the first barrel cam 500, without bending orcurving in a direction parallel with the rotational axis 550). Thestraight section 522 extends along the perimeter of the second barrelcam 502 in a relatively straight direction along the perimeter of thesecond barrel cam 502. In particular, in the flattened view shown byFIG. 5A, straight section 520 extends along axis 508, and straightsection 522 extends along axis 510, where each of axis 508 and axis 510represent paths encircling the rotational axis 550 of the first barrelcam 500 and second barrel cam 502.

As described with reference to the examples above, as the first shiftfork following pin 512 moves (e.g., slides) within the cam track 504 offirst barrel cam 500, the position of the first shift fork following pin512 within the cam track 504 adjusts the position of the first shiftfork to engage or disengage gears of the transmission. The first shiftfork is configured to engage and disengage the first and second gears ofthe transmission based on the position of the first shift fork followingpin 512 within the cam track 504. As the second shift fork following pin514 moves (e.g., slides) within the cam track 506 of second barrel cam502, the position of the second shift fork following pin 514 within thecam track 506 adjusts the position of the second shift fork to engage ordisengage at least one gear of the transmission. The second shift forkis configured to engage and disengage the third gear of the transmissionbased on the position of the second shift fork following pin 514 withinthe cam track 506. While the first shift fork following pin 512 ispositioned within straight section 520 of the cam track 504, the firstshift fork does not engage any of the gears of the transmission (e.g.,does not connect gears of the transmission to an output of thetransmission), and while the second shift fork following pin 514 ispositioned within the straight section 522 of the cam track 506, thesecond shift fork does not engage any of the gears of the transmission.In the condition shown by FIG. 5A, with the first shift fork followingpin 512 in straight section 520 and the second shift fork following pin514 in straight section 522, the transmission is in neutral (e.g., noneof the gears of the transmission are engaged, and the gears do not drivethe output of the transmission).

FIG. 5B shows the first barrel cam 500 rotated by 120 degrees around therotational axis 550 relative to the position of the first barrel cam 500shown by FIG. 5A, with the second barrel cam 502 in the same position asshown by FIG. 5A. In this configuration, the first shift fork followingpin 512 is seated within the first angled section 516 of the cam track504 of the first barrel cam 500. The first angled section 516 is formedby portions of the cam track 504 arranged at an angle relative to eachother, as indicated by angle 552 between axis 554 and axis 556, whereaxis 554 and axis 556 are each not parallel to axis 508 shown by FIG.5A. The position of the first shift fork following pin 512 within thefirst angled section 516 results in engagement of the first gear of thetransmission by the first shift fork (e.g., engagement of the first gearof the gear sequence of the transmission).

FIG. 5C shows the first barrel cam 500 rotated by 120 degrees around therotational axis 550 relative to the position of the first barrel cam 500shown by FIG. 5B, with the second barrel cam 502 in the same position asshown by FIGS. 5A-5B. For example, in transitioning between thecondition shown by FIG. 5A to the condition shown by FIG. 5B, the firstbarrel cam 500 is rotated independently of the second barrel cam 502 by120 degrees in a first direction (e.g., clockwise), and in transitioningbetween the condition shown by FIG. 5B to the condition shown by FIG.5C, the first barrel cam 500 is again rotated by 120 degrees in thefirst direction. In the configuration shown by FIG. 5C, the first shiftfork following pin 512 is seated within the second angled section 524 ofthe cam track 504 of the first barrel cam 500. The second angled section524 is formed by portions of the cam track 504 arranged at an anglerelative to each other, as indicated by angle 560 between axis 562 andaxis 564, where axis 562 and axis 564 are each not parallel to axis 508shown by FIG. 5A. The position of the first shift fork following pin 512within the second angled section 524 results in engagement of the secondgear of the transmission by the first shift fork (e.g., engagement ofthe second gear of the gear sequence of the transmission).

FIG. 5D shows the first barrel cam 500 rotated by 120 degrees around therotational axis 550 relative to the position of the first barrel cam 500shown by FIG. 5C, with the second barrel cam 502 rotated around therotational axis 550 by 120 degrees relative to the position of thesecond barrel cam 502 shown by FIGS. 5A-5C. In the configuration shownby FIG. 5D, the first shift fork following pin 512 is seated within thestraight section 520 of the cam track 504 of the first barrel cam 500,and the first shift fork does not engage any gears of the transmission.However, the second shift fork following pin 514 is seated within theangled section 518 of the cam track 506, and as a result, the secondshift fork engages the third gear of the transmission (e.g., the thirdgear of the gear sequence of the transmission is engaged). The angledsection 518 is formed by portions of the cam track 506 arranged at anangle relative to each other, as indicated by angle 570 between axis 572and axis 574, where axis 572 and axis 574 are each not parallel to axis508 shown by FIG. 5A.

FIG. 5E shows the first barrel cam 500 rotated to be in the sameconfiguration as shown by FIG. 5B (e.g., with the first gear of thetransmission engaged as a result of the position of the first shift forkfollowing pin 512 within the first angled section 516), and with thesecond barrel cam 502 in the same position as shown by FIG. 5D (e.g.,with the third gear of the transmission engaged as a result of theposition of the second shift fork following pin 514 within the angledsection 518). In the configuration shown by FIG. 5E, both of the firstgear of the transmission and the third gear of the transmission areengaged concurrently. As one example, the first gear and third gear maybe engaged concurrently in order to lock the output of the transmission,such as for maintaining a position of the vehicle during conditions inwhich the vehicle is parked and not moving. The independent rotation ofthe first barrel cam 500 and second barrel cam 502 enables the firstgear and third gear to be engaged concurrently, which may reduce a loadon other components of the vehicle configured for parking of the vehicle(e.g., a parking brake) and/or reduce a likelihood of undesired movementof the vehicle.

FIG. 5F shows the first barrel cam 500 in a transitional rotationalposition in which the first shift fork following pin 512 slides betweenthe straight section 520 and the second angled section 524.Additionally, the second barrel cam 502 is shown in a transitionalrotational position in which the second shift fork following pin 514slides between the straight section 522 and the angled section 518. Asone example, the transitional configuration shown by FIG. 5F maycorrespond to a transition from engagement of the second gear of thetransmission to engagement of the third gear of the transmission. Inparticular, the first barrel cam 500 may rotate to disengage the secondgear of the transmission, and the second barrel cam 502 may rotate toengage the third gear of the transmission. The controller (e.g.,electronic controller) may vary the rotational timing and/or rotationalspeed of the first barrel cam 500 and/or second barrel cam 502 (e.g.,via adjustment of energization of the first motor configured to drivethe first barrel cam 500 and the second motor configured to drive thesecond barrel cam 502) in order to adjust the timing of disengagement ofthe second gear of the transmission and engagement of the third gear ofthe transmission (or vice versa).

For example, because the second barrel cam 502 may be rotatedindependently of the first barrel cam 500, the controller may initiaterotation of the second barrel cam 502 to transition the engagement ofthe third gear of the transmission while the first barrel cam 500 isconcurrently rotated to disengage the second gear of the transmission.The controller may initiate rotation of the second barrel cam 502 beforethe rotation of the first barrel cam 500 has disengaged the second gearof the transmission in order to reduce a duration of the transition fromengagement of the second gear to engagement of the third gear. Thecontroller may adjust the relative timing of the rotation of the firstbarrel cam 500 and second barrel cam 502 in order to more quicklytransition from engagement of the second gear of the transmission toengagement of the third gear of the transmission, or vice versa.Further, the controller may adjust the timing of the independentrotation of the first barrel cam 500 and the timing of the independentrotation of the second barrel cam 502 in order to increasing shiftingcomfort (e.g., reduce an amount of noise and/or vibration associatedwith shifting) and/or compensate for drift of shift response time (e.g.,due to degradation of transmission components, components of the shiftassembly, etc.).

Thus, FIGS. 5A-5F show two coaxially aligned barrel cams, each of whichincludes a cam track, such that two shift forks may be movedindependently along a gear selector shaft as their following pins tracethe cam tracks. For example, the angled sections described above causethe following pins and corresponding shift forks to slide laterally intoa commanded gear selection. In the example transmission describedherein, the first shift fork is configured to engage a different numberof gears (e.g., two gears) than the second shift fork (which may onlyengage one gear). As such, the first cam track of the first barrel cammay have a different shape than the second cam track of the secondbarrel cam. As shown in FIGS. 5A-5F, the first cam track may have two ormore angled sections while the second cam track may have fewer angledsections, such as only one angled section. In this way, the two barrelcams may provide for for engagement of the third gear independent ofengagement of the first and second gears, which may provide for gearphasing, skip shifting, and/or transmission locking.

Referring to FIGS. 6-7 , flowcharts are shown illustrating examplemethods 600 and 700 for controlling operation of a transmissionincluding a shift assembly. The shift assembly may be similar to, or thesame as, the shift assembly 112 shown by FIG. 1 and/or the shiftassembly 200 shown by FIG. 2 and described above. The transmission maybe the same as or similar to transmission 104 of vehicle 100 of FIG. 1 .Method 600 describes a procedure for adjusting the transmission to acommanded gear engagement based on the presence of a shift condition,and may be executed according to instructions stored in non-transitorymemory of a controller, such as the electronic controller 110 of vehicle100 of FIG. 1 . Method 700 is a continuation of method 600 and may beexecuted by the controller responsive to certain vehicle operatingconditions (e.g., conditions in which a shift condition is present).

The systems and components described herein with reference to FIGS. 6-7may be similar to, or the same as, those discussed above with referenceto FIGS. 1-4 . However, in some examples, the methods 600 and 700 may beimplemented by other systems, processors, or components withoutdeparting from the scope of this disclosure.

Referring now to FIG. 6 , at 602, method 600 includes estimating and/ormeasuring vehicle operating conditions. Vehicle operating conditions maybe estimated based on one or more outputs of various sensors of thevehicle (e.g., such as oil temperature sensors, engine speed or wheelspeed sensors, torque sensors, cam position sensors, etc., as describedabove in reference to vehicle 100 of FIG. 1 ). Vehicle operatingconditions may include engine speed and load, vehicle speed, rotationalposition of barrel cams of the shift assembly, transmission oiltemperature, exhaust gas flow rate, mass air flow rate, coolanttemperature, coolant flow rate, engine oil pressures (e.g., oil gallerypressures), operating modes of one or more intake valves and/or exhaustvalves, electric motor speed, battery charge, engine torque output,vehicle wheel torque, etc.

At 604, method 600 includes determining transmission gear engagementbased on a rotational position of first and second barrel cams of theshift assembly (e.g., first barrel cam 202 and second barrel cam 204 ofshift assembly 200). As one example, the controller may determine thatthe first barrel cam is in a neutral rotational position (e.g., wherethe rotational position of the first barrel cam does not result inengagement of any gear of the transmission) while the second barrel camis in a non-neutral rotational position (e.g., where the rotationalposition of the second barrel cam results in engagement of a gear of thetransmission). As another example, the controller may determine that thesecond barrel cam is in a neutral rotational position (e.g., where therotational position of the second barrel cam does not result inengagement of any gear of the transmission) while the first barrel camis in a non-neutral rotational position (e.g., where the rotationalposition of the first barrel cam results in engagement of a gear of thetransmission). As another example, the controller may determine that thefirst barrel cam and the second barrel cam may each be in a non-neutralrotational position (e.g., during conditions in which multiple gears ofthe transmission are engaged in order to lock the transmission). Asanother example, the controller may determine that the first barrel camand the second barrel cam are each in a neutral rotational position(e.g., during conditions in which none of the gears of the transmissionare engaged and the transmission does not output torque to drive shaftsor other components to propel the vehicle). Various examples ofrotational positions of barrel cams are shown by FIGS. 5A-5F anddescribed above.

At 606, method 600 includes determining whether a shift condition ispresent. The shift condition may be one of a plurality of differentconditions, as determined by the controller, resulting in a commandedadjustment to the current gear engagement of the transmission via theshift assembly. For example, the controller may continuously monitor oneor more parameters (e.g., vehicle speed, accelerator pedal position,barrel cam position, etc.) and may determine that a shift condition ispresent based on the vehicle operating conditions. The determination ofa shift condition may be based on factors including an estimated and/orpredicted shifting speed, fuel efficiency, reduction of component wearand/or degradation, or a combination of these or other factors. As oneexample, the controller may determine whether a shift condition ispresent based on accelerator pedal position and vehicle speed (e.g., asshown by FIG. 9 and described below). For example, the determination ofwhether a shift condition is present may be performed by the controllervia instructions stored in non-transitory memory of the controller, withthe determination being a function of both accelerator pedal positionand vehicle speed.

The determination of whether the shift condition is present may be basedon input received by the controller from one or more sensors of thevehicle. For example, based on input from one or more cam positionsensors, the controller may determine at 604 that the transmission ofthe vehicle is operating with the first gear of the transmission engaged(e.g., the first gear in the gear sequence of the transmission, with theengagement of the first gear resulting in a relatively high gear ratioat the output of the transmission relative to other gears of thetransmission). Based on a vehicle speed sensor, the controller maydetermine that the vehicle speed and/or engine speed is above apre-determined speed at which transitioning from engagement of the firstgear to engagement of the second gear provides increased engineefficiency (e.g., to maintain the engine speed within a pre-determinedrange, where the pre-determined range includes engine speeds having arelatively high ratio of torque output versus fuel consumption). Thecontroller may also determine from the vehicle speed sensor that thevehicle speed is increasing (e.g., based on engine speed, previousvehicle speeds, change in vehicle elevation, commanded fuel injectionrate, etc.). Based on the aforementioned determinations (e.g., that thevehicle is being operated in the first gear, that the vehicle speed isabove the threshold value, and that engine speed and/or vehicle speed isincreasing), the controller may determine that a shift condition ispresent, and therefore the transmission of the vehicle may be shiftedfrom operating with the first gear engaged to operating with the secondgear engaged. Alternatively, if the controller determines that thevehicle is being operated in the second gear (e.g., the second gear inthe sequence of gear ratios), and the engine speed sensors indicate thatthe vehicle speed and/or engine speed is decreasing and that the vehiclespeed has fallen below a pre-determined speed at which transitioningfrom the second gear to the first gear provides increased engineefficiency, the controller may determine that a shift condition ispresent (e.g., that the vehicle may be shifted from second gear down tofirst gear).

The controller may determine whether or not a shift condition is presentbased on input from one or more cam position sensors (e.g., thatindicate what gear a vehicle is in) in combination with a plurality ofsensors that include engine speed sensors, wheel speed sensors, throttlesensors, pedal position sensors, oil temperature or pressure sensors,etc. The controller may determine whether the shift condition is presentbased on one or more algorithms stored in a memory of the controller,where in some examples the algorithms may be updated responsive tochanges in vehicle conditions (e.g., degradation of one or moretransmission components) and/or operating driving habits via applicationof one or more of artificial intelligence (AI), machine learning, and/ordata analytics. In some examples, the controller may determine whetherthe shift condition is present based on a pre-determined vehicleoperating mode selected by an operator of the vehicle via a user inputdevice (e.g., button, switch, touchscreen, etc.). For example, a firstvehicle operating mode may be configured such that the controllerdetermines that the shift condition is present during conditions inwhich the vehicle speed is outside of a first pre-determined range ofvehicle speeds (e.g., 10 MPH to 20 MPH) while operating with only thefirst gear of the transmission engaged. During conditions in which adifferent, second vehicle operating mode is selected, the controller maydetermine that the shift condition is present while the engine speed isoutside of a different, second pre-determined range of engine speeds(e.g., 20 MPH to 30 MPH). The first vehicle operating mode maycorrespond to a fuel economy mode, for example, while the second vehicleoperating mode may correspond to a high torque output mode.

If it is determined at 606 that a shift condition is not present, method600 proceeds to 608, and the transmission operating conditions aremaintained. Maintaining the transmission operating conditions mayinclude maintaining the current gear engagement of the transmission andnot adjusting the gear engagement. Maintaining the transmissionoperating conditions may further include continuing to receive data fromtransmission sensors such as cam position sensors, oil temperaturesensors, oil pressure sensors, etc., maintaining the flow of oil in thetransmission, etc.

However, if the controller determines at 606 that a shift condition ispresent, method 600 proceeds to 610, and the controller adjusts thetransmission directly to a commanded gear engagement by independentlyrotating the first barrel cam and/or second barrel cam based on theshift condition at 606. As described herein, adjusting the transmissiondirectly to a commanded gear engagement may include transitioningthrough configurations in which no gears of the transmission are engaged(e.g., neutral configurations). For example, if the vehicle is operatingin the second gear (e.g., the second gear in the sequence of gearratios) when the controller determines that the shift condition ispresent (e.g., the estimated and/or measured vehicle speed exceeds thethreshold vehicle speed as described above), the controller may initiatea transition from operating the transmission with the second gearengaged to operating the transmission with the third gear engaged byrotating the first barrel cam to a neutral position (e.g., a position inwhich the first barrel cam does not result in engagement of a gear ofthe transmission, such as the position shown by FIGS. 5A and 5D anddescribed above) to disengage the second gear and rotating the secondbarrel cam from a neutral position to a position in which the third gearis engaged. Although the transition from engagement of the second gearto engagement of the third gear may include briefly operating thetransmission in a neutral gear configuration (e.g., a configuration inwhich no gears of the transmission are engaged, such as while the secondgear is disengaged and before the third gear is engaged), the transitionmay be referred to as shifting directly from second gear to third gear,Similar phrasing may be utilized herein with respect to otheradjustments to the gear engagement of the transmission (e.g., shiftingdirectly from first gear to third gear or vice versa, shifting directlyfrom third gear to second gear, etc.). The commanded gear engagement isbased on operating conditions of the vehicle. One example of commandedadjustment to the gear engagement includes disengaging the first gear ofthe transmission and engaging the second gear of the transmission (e.g.,a higher or lower gear), as described above. Another example ofcommanded adjustment to the gear engagement includes disengaging thesecond gear and engaging the third gear of the transmission (e.g.,similar to the adjusting the transmission from the configuration shownby FIG. 5C, to the transitional configuration shown by FIG. 5F, and tothe configuration shown by FIG. 5D). Another example of commandedadjustment to the gear engagement includes engaging two gears of thetransmission concurrently in order to maintain a position of the vehicle(e.g., to the configuration shown by FIG. 5E during conditions in whichthe vehicle is parked and not moving, as described further below).

The adjustment of the transmission to a commanded gear engagement mayinclude controlling the speed of adjustment based on one or moreconditions. In some examples, adjusting directly to the commanded gearengagement may include controlling adjustment speed to the commandedgear engagement based on gearbox oil temperature at 612. The gearbox oiltemperature may be referred to herein as transmission oil temperatureand may be a temperature of oil within the transmission (e.g., at agearbox portion of the transmission configured to house the gears of thetransmission). As one example, the gearbox oil temperature may be atemperature of oil flowing within transmission 104 as measured bycontroller 110 via oil temperature sensor 115 shown by FIG. 1 anddescribed above. As another example, the gearbox oil temperature may bemeasured by oil temperature sensor 221 shown by FIG. 2 and describedabove. During operation of the vehicle, a temperature of the gearbox oilmay increase or decrease based on driving conditions (e.g., vehiclespeed, ambient temperature, etc.). During conditions in which thegearbox oil temperature is higher, a viscosity of the gearbox oil may bedecreased. As a result of the decreased viscosity, the gears of thetransmission may experience less resistance to movement (e.g., lessresistance to engagement or disengagement). During such conditions, arelative timing of disengagement of the second gear (e.g., a timing ofrotation of the first barrel cam to disengage the second gear) andengagement of the third gear (e.g., a timing of rotation of the secondbarrel cam to engage the third gear) may be adjusted by the controllerbased on a calculated or inferred viscosity of the gearbox oilassociated with the temperature of the gearbox oil. For example, duringconditions in which the gearbox oil temperature is below a firstthreshold value (e.g., 70 degrees Celsius, shortly after initiatingdriving), the timing of the disengagement of the second gear (e.g., thetiming of rotation of the first barrel cam) may be advanced by time A,and/or the timing of the engagement of third gear (e.g., the timing ofrotation of the second barrel cam) may be retarded by time B, in orderto provide increased time for the shifting of gears (e.g., maintain aduration between completion of disengagement of the second gear andcompletion of engagement of the third gear at a commanded duration,where the commanded duration corresponds to an amount of time resultingin increased efficiency of the transmission).

For example, without adjusting based on the temperature of the gearboxoil, the shift assembly may be operated with a rotation timing of thefirst barrel cam commanded according to a first pre-determined rotationtiming and the rotation timing of the second barrel cam commandedaccording to a second pre-determined rotation timing. In this condition,as one example, completion of the rotation of the second barrel cam mayoccur one half-second after completion of the rotation of the firstbarrel cam (e.g., the duration between disengagement of the second gearand engagement of the third gear may be one half-second, although insome examples the duration may be a different amount). However, reducingthe duration between disengagement of the second gear and engagement ofthe third gear may be desirable in order to increase an efficiency ofthe transmission (e.g., reduce a likelihood of a decrease in a torqueoutput of the transmission). In order to reduce the duration between acompletion of disengagement of the second gear and a completion ofengagement of the third gear, the controller may maintain the durationbetween disengagement of the second gear and engagement of the thirdgear at a commanded duration by adjusting the rotation timing of thefirst barrel cam from the first pre-determined timing and/or adjustingthe rotation timing of the second barrel cam from the secondpre-determined timing, where the amount of adjustment to the rotationtiming is based on the transmission oil temperature.

Adjusting the rotation timing of the first barrel cam and adjusting therotation timing of the second barrel cam relative to each other may bereferred to herein as adjusting the relative rotation timing of thefirst barrel cam and the second barrel cam. As one example, thecontroller may advance the rotation timing of the first barrel cam fromthe first pre-determined timing (e.g., initiate rotation of the firstbarrel cam earlier relative to the rotation of the first barrel camaccording to the first pre-determined timing, responsive to the shiftcondition), or the controller may retard the rotation timing of thesecond barrel cam from the second pre-determined timing (e.g., initiaterotation of the second barrel cam later relative to the rotation of thesecond barrel cam according to the second pre-determined timing,responsive to the shift condition). Adjusting the relative rotationtiming of the first barrel cam and the second barrel cam may thereforeinclude advancing the rotation timing of the first barrel cam andmaintaining the rotation timing of the second barrel cam (e.g.,maintaining the rotation timing at the second pre-determined timing).The rotation timing of the first barrel cam may be advanced by onefourth-second, or the rotation timing of the second barrel cam may beretarded by one-fourth second, in one example (e.g., during conditionsin which the oil temperature is a first, higher temperature, such as 65degrees Celsius). In another example, the rotation timing of the firstbarrel cam may be advanced by one-eighth second, or the rotation timingof the second barrel cam may be retarded by one-eighth second (e.g.,during conditions in which the oil temperature is a second, lowertemperature, such as 60 degrees Celsius). Other timing adjustments arepossible.

During conditions in which the gearbox oil temperature is above a secondthreshold value (e.g., 82 degrees Celsius, after prolonged driving), thetiming of the disengagement of the second gear may be retarded by timeC, and/or the timing of the engagement of third gear may be advanced bytime D, in order to provide the shifting of gears to occur in a shorterperiod of time. As one example, the controller may retard the rotationtiming of the first barrel cam from the first pre-determined timing(e.g., initiate rotation of the first barrel cam later relative to therotation of the first barrel cam according to the first pre-determinedtiming, responsive to the shift condition), or the controller mayadvance the rotation timing of the second barrel cam from the secondpre-determined timing (e.g., initiate rotation of the second barrel camearlier relative to the rotation of the second barrel cam according tothe second pre-determined timing, responsive to the shift condition).The rotation timing of the first barrel cam may be retarded by onefourth-second, or the rotation timing of the second barrel cam may beadvanced by one-fourth second, in one example (e.g., during conditionsin which the oil temperature is a first, higher temperature, such as 88degrees Celsius). In another example, the rotation timing of the firstbarrel cam may be retarded by one-eighth second, or the rotation timingof the second barrel cam may be advanced by one-eighth second (e.g.,during conditions in which the oil temperature is a second, lowertemperature, such as 84 degrees Celsius). Other timing adjustments arepossible.

In some examples, two or more of times A, B, C, and D may be the same,while in other examples, A, B, C, and D may be different times.

Adjusting the rotation timing of the barrel cams as described above mayadjust the shift timing of the transmission from a pre-determined shifttiming (e.g., a shift timing resulting from the first pre-determinedtiming of the first barrel cam and the second pre-determined timing ofthe second barrel cam), such that the time between disengagement of thesecond gear and engagement of the third gear, or vice versa (e.g., thetime between disengagement of the third gear and engagement of thesecond gear), is reduced. As a result, shift performance may beincreased (e.g., an amount of time to transition from one gearengagement to another may be decreased), and vehicle efficiency may beincreased (e.g., an amount of fuel, or electrical power, used to providetorque to propel the vehicle may be reduced due to a decreasedlikelihood of a reduction of torque output by the transmission). In someexamples, the pre-determined shift timing may correspond to aconventional shift timing of a conventional transmission (e.g., a shifttiming that is not adjusted based on a learning algorithm, transmissionoil temperature, or characteristics of the first barrel cam and secondbarrel cam). The adjustment of the transmission to a commanded gearengagement is discussed in further detail below with respect to FIG. 7 .

In some examples, adjusting directly to the commanded gear engagementmay include controlling adjustment speed and/or timing to the commandedgear engagement based on a learning algorithm at 614. The learningalgorithm may be a machine learning algorithm, deep neural network, etc.stored in a memory of the controller (e.g., stored in learning module111 of the controller 110 shown by FIG. 1 and described above). Thelearning algorithm may take as input shifting data collected over time,and the controller may adjust the timing and/or speed of the shifting ofthe transmission via the shift assembly based on the shifting data(e.g., to increase shifting efficiency). The shifting data used as inputmay include sensor data (e.g., from engine speed sensors, oil pressureor temperature sensors, etc.), and/or data recorded by the controller,such as transmission timing data (e.g., the start and end times of eachgear engagement and/or disengagement, etc.), historical/statistical data(e.g., total/mean continuous driving time, time spent out of operation,etc.), age of various components, maintenance and/or repair information,and/or user input (e.g., type of oil used during a given time period,type of usage, driver information, etc.), and/or any other type ofinformation relevant to shifting efficiency. The controller may adjustoperation of the shift assembly based on the shifting data by adjustingtiming for engaging and/or disengaging one or more gears when shiftingunder certain conditions, adjusting a speed of the shifting for specificgear combinations, adjusting conditions in which the controller commandsthe shift assembly to skip gears (e.g., shift directly from first gearto third gear, or vice versa), etc. The types of data described above aspotential inputs to a learning algorithm and the adjustments performedby the controller output are non-limiting, and in some examples, othertypes of data may be used.

As one example, degradation of the transmission oil (e.g., gearbox oil),gears, or other components of the transmission may result in decreasedshift performance over time (e.g., increased time to transition from onegear engagement to another). The reduction in shift performance due totransmission component degradation may be referred to herein as shifttiming drift. The controller may determine (e.g., estimate and/ormeasure) the amount of shift timing drift and may adjust operation ofthe shift assembly via the learning algorithm in order to at leastpartially counteract the shift timing drift, whereby engine, driving,and/or shifting conditions may be compared to training data collectedover a previous duration for adjusting the operation of the shiftassembly. The adjustment to the operation of the shift assembly mayinclude increasing and/or decreasing a rotation speed and/or relativerotation timing of the first barrel cam and/or the second barrel cam(e.g., a rotation speed of the first barrel cam relative to a rotationspeed of the second barrel cam, a rotation starting timing of the firstbarrel cam relative to a rotation starting timing of the second barrelcam, etc.). By adjusting the operation of the shift assembly responsiveto the shift timing drift, transmission efficiency (e.g., shiftperformance) may be increased, and a rate of increase of the shifttiming drift may be reduced (e.g., the operation of the shift assemblymay be adjusted in order to reduce further shift timing drift). Thus,shifting efficiency may be adjusted periodically and/or dynamicallyduring operation in order to accommodate a range of conditions, drivingstyles, etc.

In some examples, the learning algorithm may adjust the operation of theshift assembly in combination with the adjustments based on transmissionoil temperature described above. For example, the controller may adjustthe rotation timing of the first barrel cam by a first adjustment amount(e.g., advance the rotation timing by one eighth-second) based on theoil temperature, and the controller may further adjust the rotationtiming of the first barrel cam by a second adjustment amount (e.g.,advance the rotation timing by one sixteenth-second) based on apredicted response rate of the first barrel cam determined via thelearning algorithm. In other examples, the controller may adjust therotation timing of the first barrel cam by a single adjustment amountdetermined via the learning algorithm, where the learning algorithmdetermines the adjustment amount at least partially as a function of thetransmission oil temperature. For example, the controller may predict aresponse rate of the first barrel cam (e.g., a speed of rotation of thefirst barrel cam responsive to a given amount of energization of thefirst motor configured to drive the first barrel cam) via the learningalgorithm, and the controller may adjust (e.g., increase or decrease)the predicted response rate based on the transmission oil temperature.The controller may control the first motor via a control signal (e.g.,electronic command signal) transmitted from the controller to the firstmotor, where the control signal is based on the adjusted predictedresponse rate (e.g., the controller may determine parameters of thecontrol signal, such as a pulse width of the control signal, responsiveto the adjusted predicted response rate). As one example, the pulsewidth of the control signal may be increased or decreased responsive toconditions in which the adjusted predicted response rate is lower orhigher, respectively (e.g., in order to increase or decrease,respectively, a duty cycle of the first motor).

In some examples, the predicted response rate of the first barrel camand the predicted response rate of the second barrel cam may bedifferent (e.g., for a same, given transmission oil temperature, such as80 degrees Celsius, 75 degrees Celsius, etc.). As one example, thecontroller may determine that the predicted response rate of the secondbarrel cam is higher (e.g., faster) or lower (e.g., slower) than thepredicted response rate of the first barrel cam via the learningalgorithm. The predicted response rate of the first barrel cam and thepredicted response rate of the second barrel cam may be determined bythe controller via the learning algorithm based on vehicle operationdata measured and stored by the controller over one or more durations ofvehicle operation (e.g., several ON/OFF cycles of operation of thevehicle, as described above), with the vehicle operation data acquiredby the controller from the various sensors of the vehicle (e.g., pedalposition sensor 154, oil temperature sensor 115, wheel speed sensors113, etc. shown by FIG. 1 and described above). As one example,controller may determine via the learning algorithm and based on thevehicle operation data that a previous, measured response rate of thefirst barrel cam is slower than a previous, measured response rate ofthe second barrel cam (e.g., due to a larger number of rotations of thefirst barrel cam relative to a number of rotations of the second barrelcam). The measured response rate of a given barrel cam (e.g., the firstbarrel cam or second barrel cam), as measured by the controller from thevehicle operation data, may correspond to a duration from an initiationof a commanded rotation of the given barrel cam to a completion of thecommanded rotation of the given barrel cam, where the completion of thecommanded rotation immediately follows the initiation of the commandedrotation. The controller may compare one or more previous measuredresponse rates of the first barrel cam, for example, via the learningmodule in order to determine the predicted response rate of the firstbarrel cam (e.g., for the next commanded rotation of the first barrelcam). The controller may additionally track the transmission oiltemperature associated with each of the one or more previous measuredresponse rates of the first barrel cam with a current transmission oiltemperature in order to adjust the predicted response rate of the firstbarrel cam based on the current transmission oil temperature (e.g., thetransmission oil temperature as measured immediately prior to the nextcommanded rotation of the first barrel cam).

Referring now to FIG. 7 , a flowchart illustrating method 700 is shown,where method 700 is a continuation of the method 600 described above.Method 700 is a method for adjustment of the transmission to a commandedgear engagement, as described above at 610 of FIG. 6 . The componentsdescribed herein with reference to method 700 may be the same as thosedescribed above with reference to method 600 of FIG. 6 (e.g., method 700may be executed by the controller described above with reference to FIG.6 , the electronic controller 110 of vehicle 100 of FIG. 1 , etc.).

At 702, method 700 includes determining whether the vehicle isstationary and a park lock is requested. The determination of whetherthe vehicle is stationary may include determining the vehicle speedbased on one or more vehicle speed sensors, as described above. Theshift condition described above with reference to 606 of FIG. 6 may bethe park lock request. The determination of whether the park lock isrequested may be based on input to one or more user interface devices ofthe vehicle (e.g., a park lock button located within a cabin of thevehicle, a position of a keyed ignition switch of the vehicle, etc.).The park lock may be requested, for example, in order to reduce alikelihood of undesired movement of the vehicle. As one example, duringconditions in which a heavy load is applied to the vehicle while thevehicle is stationary and parked (e.g., on steep hills and/or while thevehicle weight is increased due to towing or hauling), it may bedifficult to maintain the position of the vehicle with the parkingbrake. However, by locking the output of the transmission, the positionof the vehicle may be more easily maintained. Locking the output of thetransmission includes engaging more than one gear of the transmissionconcurrently in order to lock a rotation of an output shaft of thetransmission (e.g., transmission output shaft 428 described above withreference to FIG. 4 ). In some examples, the park lock may be requestedby the user only during conditions in which the vehicle is stationary.As one example, the park lock may be requested during conditions inwhich signals (e.g., electronic signals) transmitted to the controllerby one or more vehicle position sensors indicate that the vehicle is notin motion and the hydraulic brake and/or parking brake is applied inorder to maintain the vehicle in the stationary position.

If the controller determines at 702 that the vehicle is stationary and apark lock is requested, method 700 proceeds to 704, and the controllerlocks the transmission output by engaging both of the first gear via thefirst barrel cam and the third gear via the second barrel cam. Asmentioned above, responsive to user input such as pushing abutton/switch, touching a touchscreen, or otherwise indicating that aparking condition is desired, the first barrel cam and the second barrelcam of the shift assembly, (e.g., the first barrel cam 202 and thesecond barrel cam 204 of shift assembly 200 of FIG. 2 ) areindependently rotated to engage both first and third gears concurrently,while the vehicle is not moving, in order to lock the geartrain of thetransmission to the stationary transmission housing. For example, theshift assembly may be adjusted by the controller to the configurationshown by FIG. 5E and described above. As one example, responsive to thedetermination that the park lock is requested at 702 and the vehicle isoperating with the first gear engaged, the controller may maintain theposition of the first barrel cam and may energize the second motorconfigured to drive the second barrel cam with a first polarity (e.g., afirst electrical voltage delta across the second motor, which may bereferred to herein as a forward polarity) in order to move the secondbarrel cam in a first direction (e.g., clockwise) and engage the thirdgear of the transmission concurrently with the engagement of the firstgear of the transmission.

If the controller determines at 702 that the vehicle is not stationary(e.g., the vehicle is moving) and the park lock is not requested, method700 proceeds from 702 to 706 where method 700 includes determiningwhether the second gear of the transmission is engaged. As described inrelation to FIG. 7 , references to “the first gear” refer to the firstgear in the sequence of gear ratios, references to “the second gear”refer to the second gear in the sequence of gear ratios, and referencesto “the third gear” refer to the third gear in the sequence of gearratios. For example, engagement of only the first gear of thetransmission may result in a transmission gear ratio of approximately3.6, engagement of only the second gear of the transmission may resultin a transmission gear ratio of approximately 2.0, and engagement ofonly the third gear of the transmission may result in a transmissiongear ratio of approximately 1.2. As one example, during operation of thevehicle on a flat, level surface, as the speed of the vehicle increases,the shift assembly may sequentially adjust the gear engagement of thetransmission from engagement of the first gear, to engagement of thesecond gear, and then to engagement of the third gear. Further, as thevehicle speed decreases, the shift assembly may sequentially adjust thegear engagement of the transmission from engagement of the third gear,to engagement of the second gear, and then to engagement of the firstgear.

At 706, the controller determines whether the second gear of thetransmission is engaged. Determining whether the second gear of thetransmission is engaged may include determining the rotational positionof the first barrel cam and second barrel cam based on signals (e.g.,electronic signals) transmitted to the controller by one or more camposition sensors, as described above. For example, the controller maydetermine that the second gear of the transmission is engaged duringconditions in which the first barrel cam and second barrel cam are inthe rotational positions shown by FIG. 5C and described above (e.g.,such that a first shift fork following pin seated within a cam track ofthe first barrel cam is in a position resulting in engagement of thesecond gear by the first shift fork, while a second shift fork followingpin seated within a cam track of the second barrel cam is in a positionresulting in no gear engagement by the second shift fork).

If the second gear of the transmission is engaged at 706, the controllerdetermines at 708 whether a shift up condition is present. For example,the controller may determine whether the shift condition described aboveat 606 of FIG. 6 is a shift up condition. The shift up condition is acondition in which the controller commands the shift assembly to adjustthe transmission to a higher gear in the gear sequence. For example, asdescribed above, the gear sequence of the transmission, in ascendingorder, may be engagement of the first gear, then engagement of thesecond gear, and then engagement of the third gear. Because the secondgear of the transmission is engaged at 706 as described above, the shiftup condition at 708 is a condition in which the controller commands theshift assembly to transition the transmission from engagement of thesecond gear to engagement of a higher gear in the gear sequence (e.g.,the third gear). In the example described herein, the transmissionincludes three gears (e.g., first gear, second gear, and third gear).However, other examples may include a different number of gears (e.g.,four gears).

In one example, the shift up condition may be a condition in which aspeed of the vehicle exceeds a threshold vehicle speed, and/or a speedof the engine exceeds a threshold engine speed. For example, thethreshold vehicle speed may be a pre-determined speed at whichtransitioning from the second gear to the third gear provides increasedengine efficiency (e.g., to maintain the engine speed within apre-determined range, where the range corresponds to a relatively highratio of torque output versus fuel consumption), or conditions forupshifting may be met as vehicle speed increases when coasting downhillas the drive motor approaches the threshold speed. In some examples, asdescribed below with reference to FIG. 9 , the shift up condition may bea function of several vehicle operating parameters, such as vehiclespeed and accelerator pedal position.

If the controller determines that the shift up condition is present at708, the method continues from 708 to 710 where the method includesdisengaging the second gear via the first barrel cam and shiftingdirectly to engagement of the third gear via the second barrel cam. Forexample, the controller may disengage the second gear by rotating thefirst barrel cam to adjust the first shift fork following pin to aneutral position resulting in no gear engagement of the transmission viathe first shift fork (e.g., a position in which neither of the firstgear or second gear are engaged), and the controller may engage thethird gear by rotating the second barrel cam to adjust the second shiftfork following pin to a non-neutral position resulting in engagement ofthe third gear of the transmission via the second shift fork. Inparticular, disengaging the second gear and engaging the third gear mayinclude adjusting the first barrel cam and second barrel cam to thepositions shown by FIG. 5D and described above. Rotating the firstbarrel cam may include energizing the first motor configured to drivethe first barrel cam with the first polarity in order to rotate thefirst barrel cam clockwise from the position shown by FIG. 5C to theposition shown by FIG. 5D, and rotating the second barrel cam mayinclude energizing the second motor configured to drive the secondbarrel cam with the first polarity in order to rotate the second barrelcam clockwise from the position shown by FIG. 5C to the position shownby FIG. 5D. As described above, a timing and/or speed of the rotation ofthe first barrel cam and the rotation of the second barrel cam, and thecorresponding disengagement and engagement of gears, may be controlledby the controller based on vehicle operating conditions in order toincrease shifting efficiency.

However, if the controller determines that the shift up condition is notpresent at 708, the method continues from 708 to 712 where the methodincludes shifting directly to first gear via the first barrel cam. Inparticular, the controller shifts the transmission from engagement ofthe second gear (e.g., similar to the configuration shown by FIG. 5C) toengagement of the first gear (e.g., similar to the configuration shownby FIG. 5B) by rotating the first barrel cam to adjust the position ofthe first shift fork via the first shift fork following pin. Rotatingthe first barrel cam to disengage the second gear and engage the firstgear may include energizing the first motor configured to drive thefirst barrel cam with a second polarity (e.g., a second electricalvoltage delta which may be referred to herein as a reverse polarity,where the reverse polarity is opposite to the forward polarity) in orderto move the first barrel cam in a second direction opposite to the firstdirection (e.g., counter-clockwise).

Returning to 706, if at 706 it is determined that the second gear of thetransmission is not engaged, the method proceeds from 706 to 714 wherethe method includes determining whether the first gear of thetransmission is engaged. Determining whether the first gear of thetransmission is engaged may include determining the rotational positionof the first barrel cam and second barrel cam based on signals (e.g.,electronic signals) transmitted to the controller by the one or more camposition sensors, as described above. For example, the controller maydetermine that the first gear of the transmission is engaged duringconditions in which the first barrel cam and second barrel cam are inthe rotational positions shown by FIG. 5B and described above (e.g.,such that a first shift fork following pin seated within a cam track ofthe first barrel cam is in a position resulting in engagement of thefirst gear by the first shift fork, while a second shift fork followingpin seated within a cam track of the second barrel cam is in a positionresulting in no gear engagement by the second shift fork). Thedetermination of whether the first gear is engaged at 706 refers todetermining whether only the first gear is engaged.

If at 714 the controller determines that only the first gear is engaged,the method proceeds from 714 to 716 where the method includesdetermining whether a skip shift condition is present. For example, thecontroller may determine whether the shift condition described above at606 of FIG. 6 is a skip shift condition. The skip shift condition is acondition in which the controller commands the shift assembly to adjustthe transmission from the current gear engagement to a different gearengagement in an order that is not the same as the gear sequence of thetransmission. For example, as described above, the gear sequence of thetransmission, in ascending order, includes engagement of the first gear,then engagement of the second gear, and then engagement of the thirdgear. However, as one example, during conditions in which the skip shiftcondition is present, the controller may command the shift assembly toadjust the gear engagement of the transmission directly from engagementof the first gear to engagement of the third gear (e.g., skippingengagement of the second gear), as described below.

In one example, the skip shift condition may be a condition in which aspeed of the vehicle exceeds a threshold vehicle speed, and/or a speedof the engine exceeds a threshold engine speed. For example, thethreshold vehicle speed may be a pre-determined speed at whichtransitioning from the first gear directly to the third gear, withoutengaging the second gear, provides increased engine efficiency (e.g., tomaintain the engine speed within a pre-determined range, where the rangecorresponds to a relatively high ratio of torque output versus fuelconsumption), or conditions for skip shifting during an upshift may bemet when vehicle speed increases rapidly when coasting downhill as thedrive motor approaches a threshold speed. In some examples, as describedbelow with reference to FIG. 9 , the skip shift condition may be afunction of several vehicle operating parameters, such as vehicle speedand accelerator pedal position.

For example, during conditions in which the vehicle is operated underheavy load (e.g., towing, hauling, etc.), the speed of the vehicle maybe increasing while operating with the first gear engaged. As the speedof the vehicle increases above the pre-determined threshold vehiclespeed (e.g., 10 miles an hour) at which the controller would normallyshift transition the transmission from engagement of the first gear toengagement of the second gear (e.g., under lower load conditions), thecontroller may determine based on vehicle operating conditions (e.g.,vehicle sensor data) that shifting to engagement of the second gear mayreduce a forward momentum of the vehicle, leading to reduced vehiclespeed and reduced fuel efficiency. The controller may determine (e.g.,via a calculation, lookup table stored in non-transitory memory, etc.)that fuel efficiency may be increased by not transitioning fromengagement of the first gear to engagement of the second gear butinstead transitioning directly from engagement of the first gear toengagement of the third gear. In some examples, the controller may delaythe transition from engagement of the first gear to engagement of thethird gear based on vehicle operating parameters such as vehicle speed(e.g., the controller may command the shift assembly to maintainengagement of the first gear until the vehicle speed is above a secondthreshold vehicle speed, such as 30 miles an hour). In this example, thecontroller may skip the engagement of the second gear in order tomaintain the forward momentum of the vehicle, and fuel efficiency may beincreased.

If at 716 it is determined that the skip shift condition is not present,the method proceeds from 716 to 720 where the method includes shiftingdirectly to second gear via the first barrel cam. In particular, thecontroller shifts the transmission from engagement of the first gear(e.g., similar to the configuration shown by FIG. 5B) to engagement ofthe second gear (e.g., similar to the configuration shown by FIG. 5C) byrotating the first barrel cam to adjust the position of the first shiftfork via the first shift fork following pin.

However, if the controller determines at 716 that the skip shiftcondition is present, the method proceeds from 716 to 718 where themethod includes disengaging the first gear via the first barrel cam andshifting directly to the third gear via the second barrel cam. Inparticular, the controller shifts the transmission from engagement ofthe first gear (e.g., similar to the configuration shown by FIG. 5B) toengagement of the third gear (e.g., similar to the configuration shownby FIG. 5D) by rotating the first barrel cam to adjust the position ofthe first shift fork via the first shift fork following pin to disengagethe first gear and by rotating the second barrel cam to adjust theposition of the second shift fork via the second shift fork followingpin to engage the third gear. As one example, because the first barrelcam and second barrel cam are rotatable independently of each other, thefirst barrel cam may be rotated in a first direction (e.g.,counter-clockwise direction) to disengage the first gear of thetransmission concurrently while the second barrel cam is rotated in anopposing, second direction (e.g., clockwise direction) to engage thethird gear of the transmission. In some examples the controller mayadjust the timing and/or speed of disengagement of the first gear andengagement of the third gear based on different vehicle operatingparameters such as transmission oil temperature, via a learningalgorithm similar to the example described above with reference to thetransition between disengagement of the second gear and engagement ofthe third gear, etc.

Returning to 714, if the controller determines that the first gear isnot engaged, the method proceeds from 714 to 722 where the controllerdetermines if the third gear is engaged and a skip shift condition ispresent. Determining whether the third gear of the transmission isengaged may include determining the rotational position of the firstbarrel cam and second barrel cam based on signals (e.g., electronicsignals) transmitted to the controller by the one or more cam positionsensors, as described above. For example, the controller may determinethat the third gear of the transmission is engaged during conditions inwhich the first barrel cam and second barrel cam are in the rotationalpositions shown by FIG. 5D and described above (e.g., such that thefirst shift fork following pin seated within the cam track of the firstbarrel cam is in a neutral position resulting in no engagement oftransmission gears by the first shift fork, while the second shift forkfollowing pin seated within the cam track of the second barrel cam is ina position resulting in engagement of the third gear of the transmissionby the second shift fork). The determination of whether the third gearis engaged at 706 refers to determining whether only the first gear isengaged.

The determination of whether the skip shift condition is present at 722may include determining whether the shift condition described above at606 of FIG. 6 is the skip shift condition. The skip shift condition is acondition in which the controller commands the shift assembly to adjustthe transmission from the current gear engagement to a different gearengagement in an order that is not the same as the gear sequence of thetransmission, as described above (e.g., transitioning directly fromengagement of the third gear to engagement of the first gear). As oneexample, the skip shift condition may be a condition in which a speed ofthe vehicle decreases below a threshold vehicle speed, and/or a speed ofthe engine decreases below a threshold engine speed. The thresholdvehicle speed may be a pre-determined speed at which transitioning fromthe third gear directly to the first gear, without engaging the secondgear, provides increased engine efficiency (e.g., to maintain the enginespeed within a pre-determined range, where the range corresponds to arelatively high ratio of torque output versus fuel consumption), orconditions for skip shifting during a downshift may be met when vehiclespeed decreases rapidly when driving uphill as the drive motorapproaches a threshold speed, in order to reduce a likelihood ofdegradation of the driveline. In some examples, as described below withreference to FIG. 9 , the skip shift condition may be a function ofseveral vehicle operating parameters, such as vehicle speed andaccelerator pedal position.

If the controller determines that the third gear is engaged and the skipshift condition is present at 722, the method continues from 722 to 724where the method includes disengaging the third gear via the secondbarrel cam and shifting directly to first gear via the first barrel cam.In particular, the controller shifts the transmission from engagement ofthe third gear (e.g., similar to the configuration shown by FIG. 5D) toengagement of the first gear (e.g., similar to the configuration shownby FIG. 5B) by rotating the second barrel cam to adjust the position ofthe second shift fork via the second shift fork following pin todisengage the third gear and by rotating the first barrel cam to adjustthe position of the first shift fork via the first shift fork followingpin to engage the first gear. As one example, because the first barrelcam and second barrel cam are rotatable independently of each other, thefirst barrel cam may be rotated in a first direction (e.g., clockwisedirection) to engage the first gear of the transmission concurrentlywhile the second barrel cam is rotated in an opposing, second direction(e.g., counter-clockwise direction) to disengage the third gear of thetransmission. In some examples the controller may adjust the timingand/or speed of engagement of the first gear and disengagement of thethird gear based on different vehicle operating parameters such astransmission oil temperature, via a learning algorithm similar to theexample described above with reference to the transition betweendisengagement of the first gear and engagement of the third gear (e.g.,as described at 718), etc.

However, if the controller determines at 722 that the skip shiftcondition is not present, the method continues from 722 to 726 where themethod includes disengaging the third gear via the second barrel cam andshifting directly to the second gear via the first barrel cam. Inparticular, although the shift condition is present as determined at 606shown by FIG. 6 , the controller determines at 722 that the shiftcondition is not the skip shift condition. As a result, at 726, thecontroller shifts the transmission from engagement of the third gear(e.g., similar to the configuration shown by FIG. 5D) to engagement ofthe second gear (e.g., similar to the configuration shown by FIG. 5C) byrotating the second barrel cam to adjust the position of the secondshift fork via the second shift fork following pin to disengage thethird gear and by rotating the first barrel cam to adjust the positionof the first shift fork via the first shift fork following pin to engagethe second gear.

Referring to FIG. 8 , a graph 800 is shown illustrating various vehicleoperating parameters for an example operation of a vehicle including atransmission and a shift assembly. Components described herein withreference to FIG. 8 may be similar to the components described above.For example, the vehicle, transmission, and shift assembly may besimilar to, or the same as, the vehicle 100, transmission 104, and shiftassembly 112 described above with reference to FIG. 1 . The shiftassembly may adjust the gear engagement of the transmission, similar tothe examples described above with reference to FIGS. 2-4 , FIGS. 5A-5E,and FIGS. 6-7 . Operation of the shift assembly is controlled by acontroller, similar to the controllers described above (e.g., electroniccontroller 110 shown by FIG. 1 and described above).

The plots shown by graph 800 illustrate operating parameters of thevehicle. In particular, plot 802 shows engine speed, plot 804 showsaccelerator pedal position, plot 806 shows vehicle speed, plot 808 showsgear engagement of the transmission, plot 810 shows an energization of afirst motor configured to drive a first barrel cam of the shift assembly(e.g., similar to the first actuator motor 212 configured to drive firstbarrel cam 202 shown by FIG. 2 , the motor configured to drive firstbarrel cam 500 described above with reference to FIGS. 5A-5F, etc.),plot 812 shows an energization of a second motor configured to drive asecond barrel cam of the shift assembly (e.g., similar to the secondactuator motor 214 configured to drive second barrel cam 204 shown byFIG. 2 , the motor configured to drive second barrel cam 502 describedabove with reference to FIGS. 5A-5F, etc.), plot 814 shows a rotationalposition of the first barrel cam (e.g., similar to the positions shownby FIGS. 5A-5E), and plot 816 shows a rotational position of the secondbarrel cam (e.g., similar to the positions shown by FIGS. 5A-5E).

It should be appreciated that the energization of the first and secondactuator motors in graph 800 may be in a positive direction (e.g.,corresponding to a first polarity, or forward polarity, as describedabove) or in a negative direction (e.g., corresponding to an opposite,second polarity, or reverse polarity, as described above), as shown inplots 810 and 812, respectively. For example, at time t3, the first andsecond motors are energized in a positive direction, while at t4, boththe first motor and the second motor are energized in a negativedirection. As the energization of the motors results in the rotation ofthe corresponding barrels, positive energization results in a rotationof the corresponding barrel in one direction, while negativeenergization results in a rotation of the corresponding barrel in theopposite direction. For example, in one embodiment, a positiveenergization of the first motor may result in a clockwise rotation ofthe first barrel (e.g., 120°), while a negative energization of thefirst motor may result in a counterclockwise rotation of the firstbarrel (e.g., 120° in the opposite direction). In another embodiment, apositive energization of the first motor may result in acounterclockwise rotation of the first barrel, while a negativeenergization of the first motor may result in a clockwise rotation ofthe first barrel. In the description below, the direction of therotation of the barrel is not described, as the rotation of the barrelmay occur in either direction without departing from the scope of thisdisclosure.

At time t0, the engine of the vehicle is off, and air and fuel are notcombusted within the engine cylinders, as indicated by plot 802. Thevehicle is stationary, as shown by plot 806, and the accelerator pedalis not engaged by a driver, as shown in plot 804. The first motor andthe second motor are not energized, as shown by plots 810 and 812, andconsequently the first barrel and second barrel are both at an initialrotational position corresponding to neutral, as shown by plots 814 and816, respectively, meaning that no gears of the transmission are engaged(as shown by plot 808).

At time t1, the driver initiates operation of the vehicle by startingthe engine and engaging the first gear of the transmission. In order toengage the first gear of the transmission, the first motor is positivelyenergized, as shown at t1 by plot 810. The positive energization of thefirst motor causes the first barrel to rotate in a first direction to arotational position corresponding to the first gear of the transmission,as shown by plot 814. The second motor is not energized, meaning thatthe rotational position of the second barrel is not adjusted, as shownby plot 812 and 816, respectively. As the first barrel rotates into arotational position corresponding to first gear, a following pin of afirst shift fork (e.g., the following pin 246 of the shift fork 222 ofFIGS. 2 and 4 ) moves along the cam track of the first barrel (e.g., camtrack 228 of first barrel cam 202 of FIG. 2 ), which in turn causes thefirst shift fork to slide along a gear selector shaft (e.g., the gearselector shaft 232 of shift assembly 200 of FIG. 2 ) in order to engagethe first gear of the transmission, as described in detail above inrelation to FIGS. 2 and 4 . The engagement of the first gear of thetransmission is indicated on graph 800 by plot 808.

Between t1 and t2, the driver adjusts the accelerator pedal position(e.g., by applying downward pressure on the accelerator pedal) andengine speed and vehicle speed both increase, as shown by plots 802 and806, respectively, responsive to the change in accelerator pedalposition (e.g., as the accelerator pedal is adjusted by a driver) asshown by plot 804. Once the vehicle is in gear, the first motor and thesecond motor are not energized, as shown by plots 810 and 812,respectively, and the rotational positions of the first barrel andsecond barrel remain in their positions established at t1.

In plot 804, accelerator pedal position is shown as increasing as thevehicle accelerates. For example, an accelerator pedal position of 0 onthe graph may indicate that no pressure is applied to the acceleratorpedal, a positive change (e.g., an increase) in the accelerator pedalposition may indicate that the vehicle is experiencing positiveacceleration, and a negative change (e.g., a decrease) in theaccelerator pedal position may indicate that the vehicle is experiencingnegative acceleration. Between t1 and t2, a positive change inaccelerator pedal position is shown in plot 804, meaning that thevehicle is experiencing positive acceleration, where vehicle speed andengine speed are both shown as increasing in plots 806 and 802,respectively.

At t2 a shift condition is met for engaging the second gear of thetransmission. As described above in relation to FIGS. 6 and 7 , theshift condition may be determined by a combination of factors, such asvehicle speed passing a threshold value, engine speed passing athreshold value, positive acceleration as indicated by accelerator pedalposition, etc. Example thresholds for vehicle speed are described infurther detail below in reference to FIG. 9 .

When the shift condition is met for engaging the second gear of thetransmission at t2, the first motor is positively energized, as shown byplot 810, which causes the first barrel to be adjusted to a rotationalposition corresponding to the second gear of the transmission, as shownby plot 814. The second motor is not energized and the second barrelremains in a rotational position corresponding to neutral, as shown byplots 812 and 816, respectively. As the first barrel rotates into arotational position corresponding to second gear, the following pin ofthe first shift fork (e.g., the following pin 246 of the shift fork 222of FIGS. 2 and 4 ) moves along the cam track of the first barrel (e.g.,cam track 228 of first barrel cam 202 of FIG. 2 ), which in turn causesthe first shift fork to slide along the gear selector shaft to engagethe second gear of the transmission. The engagement of the second gearof the transmission is indicated by plot 808.

As the second gear of the transmission is engaged, between t2 and t3 theengine speed initially decreases, as shown by plot 802, and then beginsto increase responsive to the change in accelerator pedal position(e.g., as the driver accelerates), as shown by plot 804. The vehiclespeed also continues to increase responsive to the accelerator pedalposition, as shown by plot 806.

At t3, a shift condition is met for engaging the third gear of thetransmission. When the shift condition is met for engaging the thirdgear of the transmission, the first motor is positively energized asshown by plot 810, which causes the first barrel to be adjusted to arotational position corresponding to neutral, as shown by plot 814. Asthe first barrel rotates into a rotational position corresponding toneutral, the following pin of the first shift fork slides along the camtrack of the first barrel, which in turn causes the first shift fork toslide along the gear selector shaft in order to disengage the secondgear of the transmission. Once the second gear of the transmission hasbeen disengaged, the second motor is positively energized, causing thesecond barrel to rotate into a rotational position corresponding tothird gear, as shown by plot 816. As the second barrel rotates into arotational position corresponding to third gear, a following pin of asecond shift fork (e.g., the following pin 248 of the shift fork 224 ofFIGS. 2 and 4 ) slides along the cam track of the second barrel (e.g.,cam track 230 of barrel 20 of FIG. 2 ), which in turn causes the secondshift fork to slide along the gear selector shaft to engage the thirdgear of the transmission. The engagement of the third gear of thetransmission at t3 is indicated by plot 808.

As the third gear of the transmission is engaged, between t3 and t4 theengine speed initially decreases, as shown by plot 802, and then remainsgenerally constant as the accelerator pedal position indicates anegative acceleration (e.g. deceleration by the driver), as shown byplot 804. Accordingly, the vehicle speed initially increases responsiveto an accelerator pedal position corresponding to a positiveacceleration, as shown by plot 806, and then begins to decreaseresponsive to an accelerator pedal position corresponding to a negativeacceleration.

As the vehicle speed decreases between t3 and t4, at t4 a shiftcondition is met for disengaging the third gear of the transmission andengaging the second gear of the transmission (e.g., downshifting). Whenthe shift condition is met for downshifting from the third gear of thetransmission to the second gear of the transmission, the second motor isnegatively energized as shown by plot 810, which causes the secondbarrel to be adjusted in the reverse direction to a rotational positioncorresponding to neutral, as shown by plot 814. As the second barrelrotates into the rotational position corresponding to neutral, thefollowing pin of the second shift fork slides back along the cam trackof the second barrel in the reverse direction, which in turn causes thesecond shift fork to slide along the gear selector shaft in order todisengage the third gear of the transmission. When the third gear of thetransmission is disengaged, the first motor is then negativelyenergized, causing the first barrel to rotate in the reverse directioninto a rotational position corresponding to neutral, as shown by plot816. As the first barrel rotates the opposite direction into arotational position corresponding to second gear, the following pin ofthe first shift fork slides back along the cam track of the firstbarrel, which in turn causes the first shift fork to slide along thegear selector shaft to engage the second gear of the transmission. Theengagement of the second gear of the transmission at t4 is indicated byplot 808.

When the second gear of the transmission is engaged at t4, between t4and t5 the engine speed initially increases, as shown by plot 802, andthen decreases as the vehicle speed decreases, as shown in plot 806.Shortly prior to t5 the vehicle once again accelerates, as shown by thechange in accelerator pedal position in plot 804. As the vehicleaccelerates, the vehicle speed and engine speed both increase responsiveto the accelerator pedal position as shown in plots 802 and 806,respectively.

At time t5, a shift condition is met for engaging the third gear of thetransmission. The third gear is engaged via the sequence of stepsindicated above in reference to time t3, as shown by the energization ofthe first motor and second motor at t5 in plots 810 and 812,respectively, and the corresponding rotation of the first barrel into aneutral position and the rotation of the second barrel into third gearas shown by plots 814 and 816, respectively.

It should be appreciated that at time t5, gear phasing occurs during thedisengagement of the second gear and engagement of the third gear, asshown in box 818. As described in detail above in reference to FIGS. 2-7, the energization of the second motor at t5 (as shown by plot 810)overlaps with the energization of the first motor at t5 (as shown byplot 812), such that the second barrel is rotated into a rotationalposition for third gear (as shown by plot 816) slightly before the firstbarrel fully completes its rotation into the neutral position (as shownby plot 814). As stated earlier, this gear phasing may increase shiftefficiency, thus increasing fuel efficiency and decreasing wear oncomponents of the transmission.

Between times t5 and t6, plot 804 indicates a negative change in theaccelerator pedal position (e.g., a deceleration). Accordingly, betweentimes t5 and t6, the vehicle speed and engine speed decrease, as shownby plots 806 and 802, respectively.

At time t6, a shift condition is met for disengaging the third gear ofthe transmission and engaging the second gear of the transmission.Accordingly, the vehicle downshifts from third gear into second gearaccording to the procedure described above in relation to time t4, whichis indicated by the negative energization of the second motor at t6 asshown in plot 812, followed by the negative energization of the firstmotor as shown in plot 810. Likewise, the rotation of the second barrelinto the rotational position for neutral in shown in plot 816, and thesubsequent rotation of the first barrel into the rotational position forthe second gear of the transmission is shown by plot 814.

Between times t6 and t7, plot 804 continues to indicate a negativechange in the accelerator pedal position (e.g., meaning that the driveris decreasing pressure on the accelerator in order to decelerate thevehicle). Accordingly, between times t6 and t7 the vehicle speed andengine speed decrease, as shown by plots 806 and 802, respectively.

At time t7, a shift condition is met for disengaging the second gear ofthe transmission and engaging the first gear of the transmission.Accordingly, the vehicle downshifts from second gear into first gear.The first motor is negatively energized as shown by plot 810, whichcauses the first barrel to be adjusted to a rotational positioncorresponding to first gear, as shown by plot 814. The second motor isnot energized, and the second barrel remains in a rotational positioncorresponding to neutral, as shown by plots 812 and 816, respectively.As the first barrel rotates into a rotational position corresponding tofirst gear, the first shift fork slides along the gear selector shaft toengage the first gear of the transmission, in accordance with theoperation of the barrel cam actuator as described above. The engagementof the first gear of the transmission at t7 is indicated by plot 808.

Between times t7 and t8, the driver accelerates, as shown by the plot804 which indicates that the accelerator pedal position in changing in apositive direction. The corresponding increase in vehicle and enginespeed prior to t8 is rapid, as shown by plots 806 and 802, respectively.In accordance with the rapid acceleration indicated by increase invehicle and engine speed, at t8 a shift condition is met for disengagingthe first gear of the transmission and engaging the third gear of thetransmission, thus skipping the engagement of the second gear of thetransmission, as shown by plot 808. As discussed above in reference toFIGS. 2-7 , gear skipping may increase shift efficiency in some shiftconditions.

In order to shift into the third gear of the transmission from the firstgear of the transmission, the first motor is energized in a negativedirection as indicated by plot 810, which causes the first barrel torotate into the position for neutral, as indicated by plot 814. As thefirst barrel rotates into the neutral position, the first shift forkslides along the gear selector shaft to disengage the first gear of thetransmission in accordance with the movement of the first shift fork'sfollowing pin in the cam track of the first barrel, as described above.When the first gear is disengaged by the first shift fork, the secondmotor energizes in a positive direction as shown by plot 812, rotatingthe second barrel into the rotational position for the third gear of thetransmission, as shown by plot 816. As the second barrel rotates intothe position for third gear, the second shift fork engages the thirdgear of the transmission as result of the action of the second shiftfork's following pin on the cam track of the second barrel, as describedabove.

Between t8 and t9, the engine speed decreases rapidly as the engineadjusts to the engagement of the higher gear as shown by plot 802, whilethe vehicle speed remains generally constant as shown by plot 806.Approaching time t9, the accelerator pedal position in plot 804indicates a deceleration of the vehicle, and at t9, the second motor isenergized in a negative direction as shown in plot 812, which results inthe rotation of the second barrel into the rotational position forneutral as shown by plot 816, and the corresponding disengagement of thethird gear of the transmission via the second shift fork according tothe procedure described above. Once the third gear of the transmissionhas been disengaged, the first motor is energized as shown in plot 810,and the first barrel is rotated into the position corresponding to thesecond gear of the transmission, as shown in plot 814, and the secondgear of the transmission is engaged via the first shift fork, accordingto the procedure described above. The engagement of second gear at timet9 is indicated by plot 808.

Between time t9 and t10, the engine speed initially increases and thendecreases as the engine adjusts to the lower gear ratio, and then thevehicle accelerates slightly as shown by the accelerator pedal positionplot 804, and the vehicle speed and engine speed increase as shown byplots 806 and 802, respectively. At t10, a shift condition is met forengaging the third gear of the transmission. When the shift condition ismet for engaging the third gear of the transmission, the first motor ispositively energized as shown by plot 810, which causes the first barrelto be adjusted to a rotational position corresponding to neutral, asshown by plot 814, which in turn causes the first shift fork to slidealong the gear selector shaft in order to disengage the second gear ofthe transmission. Once the second gear of the transmission has beendisengaged, the second motor is positively energized, causing the secondbarrel to rotate into a rotational position corresponding to third gear,as shown by plot 816, which in turn causes the second shift fork toslide along the gear selector shaft to engage the third gear of thetransmission. The engagement of the third gear of the transmission at t3is indicated by plot 808.

Between time t10 and t11, the vehicle accelerates slightly and thenrapidly decelerates as shown by the accelerator pedal position plot 804,with a corresponding rapid decrease in the vehicle speed and enginespeed as shown by plots 806 and 802, respectively. At t11, a shiftcondition is met for disengaging from the third gear of the transmissionand engaging the first gear of the transmission, skipping the engagementof the second gear of the transmission. The procedure for downshiftingfrom the third gear of the transmission directly into first gear of thetransmission without engaging the second gear of the transmission is thereverse of the procedure mentioned above for shifting from the firstgear of the transmission directly into the third gear of thetransmission without engaging the second gear of the transmission. Thesecond motor is energized in a negative direction as shown by plot 812,in order to rotate the second barrel into the rotational position forneutral as shown by plot 816, thus disengaging the third gear, and thefirst motor is consequently energized in a positive direction as shownby plot 810, in order to rotate the first barrel into the rotationalposition for first gear as shown by plot 814, thus engaging the firstgear of the transmission.

Between time t11 and t12, plot 804 indicates that the accelerator pedalposition returns to its initial state, e.g., that no pressure is appliedto the accelerator pedal by the driver. Plot 806 shows that the enginespeed decreases to zero, indicating that the vehicle is stationary. Plot802 indicates that the engine speed decreases but does not drop to zero,indicating that the vehicle is idling in neutral (e.g., with no gearsengaged) when time t12 is reached. At time t12, the first motor isenergized in a negative direction as shown by plot 810, rotating thefirst barrel from the rotational position corresponding to first gear tothe rotational position corresponding to neutral as shown by plot 814,thus disengaging from the first gear of the transmission as shown byplot 808, and the engine is turned off.

At time t13, the accelerator pedal position, vehicle speed, and enginespeed are at zero as indicated by plots 804, 806, and 802, respectively,and the vehicle is parked by engaging the first and third gears of thetransmission simultaneously. The first motor is energized in a positivedirection as shown by plot 810, which rotates the first barrel from aneutral position into the rotational position for first gear, as shownby plot 814. Concurrently, the second motor is energized, as shown byplot 812, which rotates the second barrel into the rotational positionfor third gear, as shown by plot 816. Both the first gear and the thirdgear of the transmission are shown as engaged at 808, indicating thatthe vehicle transmission is in a parked state, whereby no rotation ofthe output shaft (e.g., output shaft 428 of FIG. 4 ) is permitted, andthe drive wheels (e.g. drive wheels 122 and 120 of FIG. 1 ) areprevented from moving.

Referring now to FIG. 9 , a graph 900 is shown including various plotsillustrating a shift schedule of a vehicle including a transmission anda shift assembly according to the examples described above. Componentsdescribed herein with reference to FIG. 9 may be similar to thecomponents described above. For example, the vehicle, transmission, andshift assembly may be similar to, or the same as, the vehicle 100,transmission 104, and shift assembly 112 described above with referenceto FIG. 1 . The shift assembly may adjust the gear engagement of thetransmission, similar to the examples described above with reference toFIGS. 2-4 , FIGS. 5A-5E, and FIGS. 6-7 . Operation of the shift assemblyis controlled by a controller, similar to the controllers describedabove (e.g., electronic controller 110 shown by FIG. 1 and describedabove).

Graph 900 shows vehicle speed along the horizontal axis and acceleratorpedal position along the vertical axis. The accelerator pedal positionmay correspond to a commanded torque output of the vehicle (e.g., acommanded torque output of the engine and/or electric motor configuredto provide torque to propel the vehicle). Plot 904 indicates therelationship between vehicle speed and accelerator pedal position thatresults in a shift condition of shifting from engagement of the firstgear of the transmission to engagement of the second gear of thetransmission (e.g., upshifting from first gear). In particular, for agiven accelerator pedal position, plot 904 illustrates a thresholdvehicle speed at which the controller commands the shift assembly toadjust (e.g., transition) the gear engagement of the transmission fromfirst gear to second gear. Similarly, plot 908 indicates therelationship between vehicle speed and accelerator pedal position thatresults in a shift condition of shifting from engagement of the secondgear of the transmission to engagement of the third gear of thetransmission. For a given accelerator pedal position, plot 908illustrates a threshold vehicle speed at which the controller commandsthe shift assembly to adjust the gear engagement of the transmissionfrom second gear to third gear.

Plot 902 indicates the relationship between vehicle speed andaccelerator pedal position that results in a shift condition of shiftingfrom engagement of the second gear of the transmission to engagement ofthe first gear of the transmission (e.g., downshifting from secondgear). In particular, for a given accelerator pedal position, plot 902illustrates a threshold vehicle speed at which the controller commandsthe shift assembly to adjust (e.g., transition) the gear engagement ofthe transmission from second gear to first gear. Similarly, plot 906indicates the relationship between vehicle speed and accelerator pedalposition that results in a shift condition of shifting from engagementof the third gear of the transmission to engagement of the second gearof the transmission. For a given accelerator pedal position, plot 906illustrates a threshold vehicle speed at which the controller commandsthe shift assembly to adjust the gear engagement of the transmissionfrom third gear to second gear. Plot 902 is plotted at a lower vehiclespeed than plot 904 and, as stated above, downshifting from second gearinto first gear and upshifting from first gear into second gear mayoccur at different vehicle speeds. This may reduce a likelihood that acontroller of the vehicle (e.g., the electronic controller 110 of FIG. 1) determines alternating shift up conditions and shift down conditionsas vehicle speed is maintained at or around a single threshold forshifting up or shifting down.

Graph 900 additionally includes a first marker 910, second marker 912,third marker 914, fourth marker 916, fifth marker 918, sixth marker 920,and seventh marker 922. The various markers are shown to indicateoperating conditions of the vehicle in which the transmission iscommanded to shift directly from first gear to third gear, or viceversa. For example, during some conditions, the controller may commandthe shift assembly of the vehicle to shift out of the gear sequence ofthe transmission by disengaging the first gear of the transmission andengaging the third gear of the transmission, without engaging the secondgear of the transmission during the transition from engagement of thefirst gear to engagement of the third gear.

As one example, the vehicle may be operating at a relatively low vehiclespeed and a relatively high amount of throttle opening (e.g., arelatively high engine load corresponding to a large amount ofaccelerator pedal depression) with the first gear of the transmissionengaged, as indicated by the first marker 910. The vehicle speed mayincrease to the amount indicated by the second marker 912. However, ifthe vehicle is operating with the vehicle speed and accelerator pedalposition indicated by second marker 912 and the accelerator pedal isthen quickly released (e.g., the driver of the vehicle stops pressingthe accelerator pedal), the controller determine that a rate of changeof the commanded torque output is greater than a threshold rate ofchange, and as a result, the controller may command the shift assemblyto transition directly from engagement of the first gear to engagementof the third gear. For example, the vehicle condition may transitionfrom the condition indicated by second marker 912 (e.g., in which thevehicle is operated with the first gear engaged) to the conditionindicated by the sixth marker 920 (e.g., in which the vehicle isoperated with the third gear engaged), without transitioning fromengagement of the first gear to engagement of the third gear. As anotherexample, the controller may command the shift assembly to transitiondirectly from engagement of the first gear to engagement of the thirdgear during conditions in which the vehicle is operating in a fueleconomy mode with a relatively large amount of accelerator pedalposition (e.g., the controller may determine that a rate of change ofthe vehicle speed is greater than a threshold rate of change). Forexample, the operating condition of the vehicle may transition from thecondition shown by first marker 910 to the condition shown by fourthmarker 916, where the first gear is engaged in the condition indicatedby first marker 910 and the third gear is engaged in the condition shownby fourth marker 916. The transition from the condition shown by firstmarker 910 to the condition shown by fourth marker 916 occurs withoutengagement of the second gear of the transmission.

During some conditions, the controller may command the shift assembly toshift directly from third gear to first gear, without engaging thesecond gear of the transmission during the transition. For example, thevehicle may transition from operating in the condition indicated bysixth marker 920 to the condition indicated by third marker 914, wherethe third gear of the transmission is engaged while in the conditionindicated by the sixth marker 920, and the first gear of thetransmission is engaged while in the condition indicated by the thirdmarker 914. The transition from the condition indicated by the sixthmarker 920 to the condition indicated by the third marker 914 may occurresponsive to a relatively sudden increase in accelerator pedaldepression (e.g., a large increase in the amount of throttle opening,where the controller determines that a rate of change of the commandedtorque output is greater than a threshold rate of change). As anotherexample, the vehicle may transition from operating in the conditionindicated by seventh marker 922 to the condition indicated by fifthmarker 918, where the third gear of the transmission is engaged while inthe condition indicated by the seventh marker 922, and the first gear ofthe transmission is engaged while in the condition indicated by thefifth marker 918. The transition from operating in the conditionindicated by the seventh marker 922 to the condition indicated by thefifth marker 918 may occur without engagement of the second gear, andmay occur responsive to a relatively quick stopping of the vehicle(e.g., decreasing the speed of the vehicle quickly from the amountindicated by the seventh marker 922 to the amount indicated by the fifthmarker 918, with the controller determining that a rate of change of thevehicle speed is greater than a threshold rate of change). Otherexamples are possible.

The controller may adjust the rotation timing of the first barrel camand the rotation timing of the second barrel cam based on theaccelerator pedal position (e.g., the commanded torque output of thevehicle) and the vehicle speed according to the examples described abovewith reference to graph 900 (e.g., the controller may adjust therotation timing of the first barrel cam and/or the rotation timing ofthe second barrel cam to disengage the first gear and shift directly toengagement of the second gear or third gear, to disengage the third gearand shift directly to engagement of the second gear or first gear, toengage both of the first gear and third gear for parking of the vehicle,etc.).

Further, in some examples, the controller may adjust the rotation timingof the first barrel cam and the rotation timing of the second barrel camto provide a commanded duration (e.g., commanded transition duration)between disengagement of one gear (e.g., the second gear in the gearsequence of the transmission) and engagement of another gear (e.g., thethird gear in the gear sequence of the transmission), where thecommanded duration may be a function of vehicle speed and/or acceleratorpedal position (e.g., the commanded torque output of the vehicle).

As one example, while transitioning from engagement of the second gearto engagement of the third gear at a lower, first vehicle speed and afirst accelerator pedal position (e.g., during conditions indicated bymarker 921), the controller may adjust the relative rotation timing ofthe first barrel cam and second barrel cam to provide a first commandedduration between disengagement of the second gear and engagement of thethird gear. However, while transitioning from engagement of the secondgear to engagement of the third gear at the same, first vehicle speedand a second accelerator pedal position (e.g., during conditionsindicated by marker 923), the controller may adjust the relativerotation timing of the first barrel cam and second barrel cam to providea second commanded duration between disengagement of the second gear andengagement of the third gear, where the second commanded duration may bedifferent than the first commanded duration (e.g., a shorter amount oftime relative to the first commanded duration). Further still, whiletransitioning from engagement of the second gear to engagement of thethird gear at a higher, second vehicle speed and a third acceleratorpedal position (e.g., during conditions indicated by marker 925), thecontroller may adjust the relative rotation timing of the first barrelcam and second barrel cam to provide a third commanded duration betweendisengagement of the second gear and engagement of the third gear, wherethe third commanded duration may be different than the first commandedduration and/or second commanded duration (e.g., a shorter amount oftime relative to the first commanded duration and/or second commandedduration). Although the transition from engagement of second gear toengagement of third gear is described above as an example, thecontroller may adjust the relative rotation timing of the first barrelcam and second barrel cam responsive to other gear engagementtransitions (e.g., while transitioning from engagement of the first gearto engagement of the second gear or vice versa, while transitioning fromengagement of the first gear directly to engagement of the third gear orvice versa, etc.)

According to the examples described above, the controller may adjust therelative rotation timing of the first barrel cam and the second barrelcam based on the vehicle speed and/or accelerator pedal position. Forexample, the relative rotation timing of the first barrel cam and thesecond barrel cam may be a function of vehicle speed, accelerator pedalposition (e.g., commanded torque output of the vehicle), and the gearengagement configuration of the transmission (e.g., the configuration inwhich the first gear is engaged, the configuration in which the secondgear is engaged, etc.). Providing the different commanded durations mayincrease a responsiveness of the shift assembly and transmission and/orreduce a likelihood of degradation of components of the shift assemblyand transmission (e.g., reduce a likelihood of wear of the first barrelcam and/or second barrel cam), and other examples are possible.

Further, the plots illustrated by graph 900 (e.g., plot 902, plot 904,plot 906, and plot 908) are provided as non-limiting examples. Thecontroller controls the shift timing by controlling the rotation timingof the first barrel cam and controlling the rotation of the secondbarrel cam, and in some examples the controller may adjust the shifttiming to be different from the examples shown by FIG. 9 . As oneexample, the controller may adjust the shift timing by adjusting therotation timing of the first barrel cam to control the vehicle speedand/or accelerator pedal position at which the transmission shifts fromengagement of the first gear to engagement of the second gear(illustrated by plot 904). An example adjustment to the shift timing isillustrated by plot 905, where plot 905 is shifted leftward along graph900 relative to plot 904 but includes the same contour as plot 904. Plot905 represents an alternative plot of vehicle speed and acceleratorpedal position associated with shifting from engagement of the firstgear to engagement of the second gear. For example, the shift timing mayutilize the relationship illustrated by plot 905 rather than therelationship illustrator by plot 904 responsive to selection of adifferent operating mode (e.g., a different performance mode) of thevehicle by an operator of the vehicle (e.g., a driver). Whilecontrolling the shift timing according to the vehicle speed andaccelerator pedal position relationship illustrated by plot 905, therotation timing of the first barrel cam is advanced relative to therotation timing of the first barrel cam while controlling the shifttiming according to the relationship illustrated by plot 904. Althoughplot 904 and plot 905 are described above as one example, other examplesare possible.

In the example described above, adjusting the shift timing is achievedby adjusting only the rotation timing of the first barrel cam, becausethe engagement of the first gear of the transmission and the engagementof the second gear of the transmission are each controlled by only thefirst barrel cam and not the second barrel cam. The transmission maytransition directly between engagement of the first gear and engagementof the second gear with the adjusted shift timing (e.g., the shifttiming utilizing the adjusted rotation timing of the first barrel cam).In particular, adjusting the shift timing to advance the transitionbetween engagement of the first gear and engagement of the second gear(e.g., by advancing the rotation timing of the first barrel cam) mayresult in the controller determining that a shift condition is presentat lower vehicle speeds (e.g., a threshold speed corresponding toinitiation of the transition may be lowered) and/or less acceleratorpedal depression amounts, while adjusting the shift timing to retard thetransition between engagement of the first gear and engagement of thesecond gear (e.g., by retarding the rotation timing of the first barrelcam) may result in the controller determining that a shift condition ispresent at higher vehicle speeds (e.g., the threshold speedcorresponding to initiation of the transition may be increased) and/orgreater accelerator pedal depression amounts. For example, the shifttiming may be adjusted by adjusting the rotation timing of only thefirst barrel cam so that the transmission initiates the transition fromengagement of the first gear to engagement of the second gear duringconditions represented by locations along plot 905 instead of conditionsrepresented by locations along plot 904.

As another example, adjusting the shift timing may be achieved byconcurrently adjusting each of the rotation timing of the first barrelcam and the rotation timing of the second barrel cam. For example, whileadjusting from engagement of the first gear or second gear of thetransmission to engagement of the third gear of the transmission, bothof the first barrel cam and the second barrel cam may be rotated (e.g.,in order to disengage the first gear or the second gear and to engagethe third gear). The transmission may transition directly betweenengagement of the first gear or second gear and engagement of the thirdgear with the adjusted shift timing (e.g., the shift timing utilizingthe adjusted rotation timing of the first barrel cam and the adjustedrotation timing of the second barrel cam). Adjusting the shift timing toadvance the transition between engagement of the first gear or thesecond gear and engagement of the third gear (e.g., by advancing therotation timing of each of the first barrel cam and the second barrelcam) may result in the controller determining that a shift condition ispresent at lower vehicle speeds (e.g., a threshold speed correspondingto initiation of the transition may be lowered) and/or less acceleratorpedal depression amounts, while adjusting the shift timing to retard thetransition between engagement of the first gear or second gear and theengagement of the third gear (e.g., by retarding the rotation timing ofeach of the first barrel cam and the second barrel cam) may result inthe controller determining that a shift condition is present at highervehicle speeds (e.g., the threshold speed corresponding to initiation ofthe transition may be increased) and/or greater accelerator pedaldepression amounts. For example, as described above, the shift timingmay be adjusted by adjusting each of the rotation timing of the firstbarrel cam and the rotation timing of the second barrel cam so that thetransmission initiates the transition from engagement of the first gearor second gear to engagement of the third gear during conditionsrepresented by locations along plot 909 instead of conditionsrepresented by locations along plot 908.

Further, in some examples, the shift timing may be adjusted by adjustingthe rotation timing of the first barrel cam and the rotation timing ofthe second barrel cam, and, responsive to a condition such as a rate ofchange of the commanded torque output exceeding a threshold rate ofchange or a rate of change of the vehicle speed exceeding a thresholdrate of change, the transmission may transition between engagement ofthe first gear or the second gear directly to engagement of the thirdgear (or vice versa) with the adjusted rotation timing. As one example,the vehicle may transition from the condition indicated by the sixthmarker 920 to the condition indicated by the third marker 914 asdescribed above (e.g., responsive to the rate of change of the commandedtorque output exceeding the threshold rate of change), or the vehiclemay be operating with the vehicle speed and accelerator pedal positionindicated by second marker 912 and the accelerator pedal is then quicklyreleased (e.g., the driver of the vehicle stops pressing the acceleratorpedal, with the rate of change of the commanded torque output exceedingthe threshold rate of change). As another example, the vehicle may beoperating in the fuel economy mode with a relatively large amount ofaccelerator pedal position as described above (e.g., with the controllerdetermining that a rate of change of the vehicle speed is greater thanthe threshold rate of change), or the vehicle speed may decrease quicklyfrom the amount indicated by the seventh marker 922 to the amountindicated by the fifth marker 918 as described above (e.g., with thecontroller determining that a rate of change of the vehicle speed isgreater than the threshold rate of change). Other examples are possible.

In this way, the inclusion of a split-barrel cam with two independentlyoperated, coaxially aligned barrel cams in a shift assembly of anautomated manual transmission, as described herein, may result in anumber of advantages over a single barrel cam. In particular, shiftefficiency may be increased by employing gear phasing or gear skipping,as described above, which in turn may increase fuel efficiency, reducewear on parts, and improve shift performance from the point of view ofan operator. Shift efficiency may also be adjusted dynamically or overthe lifetime of a transmission, such that shift efficiency is maintainedas operating conditions change or components experience wear.Additionally, the independent operation of two small barrel cams in thearrangement described herein, as opposed to a single large barrel cam,may lead to reductions in the size of the actuator motors that rotatethe barrels and/or the amount of power used to rotate the barrels.Further, the independent operation of separate barrel cams may providefor multiple gears of a transmission to be engaged concurrently, toprovide a transmission locking functionality that may serve as anadditional parking mechanism.

An embodiment relates to a system including a shift assembly for atransmission, comprising: a first barrel cam including a first camtrack; a second barrel cam arranged coaxially with the first barrel camand including a second cam track; a first motor configured to drive thefirst barrel cam independent of the second barrel cam; and a secondmotor configured to drive the second barrel cam independent of the firstbarrel cam. In a first example of the system, the first barrel cam issupported within a housing of the shift assembly by a first bearing, thesecond barrel cam is supported within the housing by a second bearing,and the first bearing, the second bearing, the first barrel cam, and thesecond barrel cam are arranged along a common axis, and wherein thecommon axis is a rotational axis of the first barrel cam and the secondbarrel cam. In a second example of the system, which optionally includesthe first example, the shift assembly includes a bushing arrangedbetween the first barrel cam and the second barrel cam, the first barrelcam and second barrel cam coupled by the bushing and rotatableindependent of each other via the bushing. In a third example of thesystem, which optionally includes one or both of the first and secondexamples, the first barrel cam is coupled to the first motor by a firstgear assembly arranged at a first side of the bushing, and the secondbarrel cam is coupled to the second motor by a second gear assemblyarranged at an opposing, second side of the bushing. In a fourth exampleof the system, which optionally includes one or more or each of thefirst through third examples, the shift assembly further includes afirst shift fork including a first following pin seated within the firstcam track, and a second shift fork including a second following pinseated within the second cam track. In a fifth example of the system,which optionally includes one or more or each of the first throughfourth examples, the first following pin is slideable within the firstcam track to a first position and a second position, where, while thefirst following pin is in the first position, the first shift fork is ina first gear engagement position, and while the first following pin isin the second position, the first shift fork is in a second gearengagement position. In a sixth example of the system, which optionallyincludes one or more or each of the first through fifth examples, thesecond following pin is slideable within the second cam track to a thirdposition, where, while the second following pin is in the thirdposition, the second shift fork is in a third gear engagement position.In a seventh example of the system, which optionally includes one ormore or each of the first through sixth examples, the first barrel camis rotatable via the first motor in a first direction and an opposing,second direction, and the second barrel cam is rotatable via the secondmotor in the first direction and the opposing, second directionindependent of the first barrel cam.

An embodiment is directed to a method including controlling a rotationalposition of a first barrel cam of a shift assembly of a transmissionaround a rotational axis via a first motor; and controlling a rotationalposition of a second barrel cam of the shift assembly around therotational axis via a second motor, independent of the rotationalposition of the first barrel cam. In a first example of the method,controlling the rotational position of the first barrel cam around therotational axis includes energizing the first motor to rotate the firstbarrel cam in a first direction or an opposing, second direction, andcontrolling the rotational position of the second barrel cam around therotational axis includes energizing the second motor to rotate thesecond barrel cam in the first direction or the opposing, seconddirection. In a second example of the method, which optionally includesthe first example, controlling the rotational position of the firstbarrel cam includes controlling the rotational position of the firstbarrel cam to a first position to engage a first gear of thetransmission and controlling the rotational position of the first barrelcam to a second position to engage a second gear of the transmission. Ina third example of the method, which optionally includes one or both ofthe first and second examples, controlling the rotational position ofthe second barrel cam includes controlling the rotational position ofthe second barrel cam to a third position to engage a third gear of thetransmission. In a fourth example of the method, which optionallyincludes one or more or each of the first through third examples, themethod includes, during a first condition, controlling the rotationalposition of the first barrel cam from the first position to the secondposition to disengage the first gear and engage the second gear, whilethe rotational position of the second barrel cam remains in a secondneutral position; and during a second condition, controlling therotational position of the first barrel cam from the first position tothe first neutral position and controlling the rotational position ofthe second barrel cam from the second neutral position to the thirdposition to disengage the first gear and engage the third gear, withoutengaging the second gear there between. In a fifth example of themethod, which optionally includes one or more or each of the firstthrough fourth examples, the method further includes, prior to or duringthe controlling of the rotational position of the second barrel cam tothe third position to engage the third gear of the transmission,controlling the rotational position of the first barrel cam to a firstneutral position to disengage the first gear or the second gear, whereinthe energization of the first motor to control the rotational positionof the first barrel cam to the first neutral position and theenergization of the second motor to control the rotational position ofthe second barrel cam to the third position are timed to commenceengagement of the third gear before the first or second gear is fullydisengaged. In a sixth example of the method, which optionally includesone or more or each of the first through fifth examples, the vehicle isstationary and controlling the rotational position of the first barrelcam includes controlling the rotational position of the first barrel camto the first position to engage the first gear of the transmission, andcontrolling the rotational position of the second barrel cam includescontrolling the rotational position of the second barrel cam to thethird position to engage the third gear of the transmission concurrentlywith the controlling of the rotational position of the first barrel cam.

An embodiment of a transmission for a vehicle includes a first barrelcam including a first cam track; a second barrel cam arranged coaxiallywith the first barrel cam and including a second cam track; a firstmotor configured to drive the first barrel cam; a second motorconfigured to drive the second barrel cam independent of the firstbarrel cam; a first shift fork including a first following pin seatedwithin the first cam track; a second shift fork including a secondfollowing pin seated within the second cam track; a transmission inputshaft including a first gear, a second gear, and a third gear; and acontroller with computer readable instructions stored on non-transitorymemory that when executed, cause the controller to: responsive to afirst command, energize the first motor to adjust a rotational positionof the first barrel cam from a first position to a second position,thereby moving the first following pin and shifting a lateral positionof the first shift fork to disengage the first gear and engage thesecond gear; and responsive to a second command, energize the secondmotor to adjust a rotational position of the second barrel cam to athird position, thereby moving the second following pin and shifting alateral position of the second shift fork to engage the third gear. In afirst example of the transmission, the second barrel cam moves from asecond neutral position to the third position responsive to the secondcommand, wherein the second barrel cam remains in the second neutralposition responsive to the first command, and wherein the instructionsfurther cause the controller to, responsive to the second command,energize the first motor to adjust the rotational position of the firstbarrel cam to a first neutral position where the second gear isdisengaged. In a second example of the transmission, which optionallyincludes the first example, the first motor is energized to rotate thefirst barrel cam in a first direction responsive to the first commandand the first motor is energized to rotate the first barrel cam in asecond, opposing direction responsive to the second command. In a thirdexample of the transmission, which optionally includes one or both ofthe first and second examples, a timing of the energization of the firstmotor and the energization of the second motor responsive to the secondcommand is controlled to commence engagement of the third gear beforethe second gear is fully disengaged. In a fourth example of thetransmission, which optionally includes one or more or each of the firstthrough third examples, the instructions further cause the controllerto, responsive to a third command: energize the first motor to adjustthe rotational position of the first barrel cam from the first positionto the first neutral position, thereby moving the first following pinand shifting the lateral position of the first shift fork to disengagethe first gear; and energize the second motor to adjust the rotationalposition of the second barrel cam to the third position, thereby movingthe second following pin and shifting the lateral position of the secondshift fork to engage the third gear.

The technical effect of including an actuator with a split-barrel cam ina shift assembly of an automated manual transmission as described hereinis that shift efficiency and fuel efficiency may be increased via theindependent operation of the two barrels of the split-barrel cam,leading to reduced wear in actuator components. Further, the independentoperation of the two barrels of the split-barrel cam may result inadditional benefits, such as reducing the dimensions of the shiftassembly and/or reducing the amount of power used to actuate the gearsof the shift assembly.

FIGS. 2-4 show example configurations with relative positioning of thevarious components. If shown directly contacting each other, or directlycoupled, then such elements may be referred to as directly contacting ordirectly coupled, respectively, at least in one example. Similarly,elements shown contiguous or adjacent to one another may be contiguousor adjacent to each other, respectively, at least in one example. As anexample, components laying in face-sharing contact with each other maybe referred to as in face-sharing contact. As another example, elementspositioned apart from each other with only a space there-between and noother components may be referred to as such, in at least one example. Asyet another example, elements shown above/below one another, at oppositesides to one another, or to the left/right of one another may bereferred to as such, relative to one another. Further, as shown in thefigures, a topmost element or point of element may be referred to as a“top” of the component and a bottommost element or point of the elementmay be referred to as a “bottom” of the component, in at least oneexample. As used herein, top/bottom, upper/lower, above/below, may berelative to a vertical axis of the figures and used to describepositioning of elements of the figures relative to one another. As such,elements shown above other elements are positioned vertically above theother elements, in one example.

In another representation, a method for a transmission of a vehicleincludes responsive to a first condition, controlling a rotationalposition of a first barrel cam of the transmission from a first positionto a second position to disengage a first gear of the transmission andengage a second gear of the transmission, while a rotational position ofa second barrel cam of the transmission remains in a second neutralposition; responsive to a second condition, controlling the rotationalposition of the first barrel cam from the first position to a firstneutral position to disengage the first gear and controlling therotational position of the second barrel cam from the second neutralposition to a third position to engage a third gear of the transmission,without engaging the second gear there between, where the controlling ofthe rotational position of the second barrel cam to the third positionis initiated before the first gear is fully disengaged.

In another representation, a method comprises: controlling a rotationalposition of a first barrel cam of a shift assembly of a transmissionaround a rotational axis via a first motor; controlling a rotationalposition of a second barrel cam of the shift assembly around therotational axis via a second motor, independent of the rotationalposition of the first barrel cam; and adjusting a shift timing of thetransmission via the first barrel cam and the second barrel camresponsive to an oil temperature of the transmission. In a first exampleof the method, adjusting the shift timing based on the oil temperatureincludes adjusting a relative rotation timing of the first barrel camand the second barrel cam based on the oil temperature. A second exampleof the method optionally includes the first example, and furtherincludes wherein adjusting the shift timing based on the oil temperatureincludes adjusting the shift timing from a pre-determined shift timing.A third example of the method optionally includes one or both of thefirst and second examples, and further includes wherein adjusting therelative rotation timing of the first barrel cam and the second barrelcam includes reducing a duration between disengagement of a second gearof the transmission and engagement of a third gear of the transmission.A fourth example of the method optionally includes one or more or eachof the first through third examples, and further includes whereinreducing the duration between disengagement of the second gear of thetransmission and engagement of the third gear of the transmissionincludes advancing a rotation of the second barrel cam relative to arotation of the first barrel cam responsive to the oil temperature. Afifth example of the method optionally includes one or more or each ofthe first through fourth examples, and further includes whereinadjusting the relative rotation timing of the first barrel cam and thesecond barrel cam includes maintaining a duration between disengagementof a second gear of the transmission and engagement of a third gear ofthe transmission. A sixth example of the method optionally includes oneor more or each of the first through fifth examples, and furtherincludes wherein maintaining the duration between disengagement of thesecond gear of the transmission and engagement of a third gear of thetransmission includes retarding a rotation of the second barrel camrelative to a rotation of the first barrel cam responsive to the oiltemperature. A seventh example of the method optionally includes one ormore or each of the first through sixth examples, and further includeswherein adjusting the relative rotation timing includes controlling arotation speed of the first barrel cam and a rotation speed of thesecond barrel cam based on the oil temperature. An eighth example of themethod optionally includes one or more or each of the first throughseventh examples, and further includes wherein controlling the rotationspeed of the first barrel cam includes controlling an energization of afirst motor configured to drive the first barrel cam, and controllingthe rotation speed of the second barrel cam includes controlling anenergization of a second motor configured to drive the second barrelcam. A ninth example of the method optionally includes one or more oreach of the first through eighth examples, and further includes whereincontrolling the energization of the first motor includes adjusting aduty cycle of the first motor, controlling the energization of thesecond motor includes adjusting a duty cycle of the second motor. Atenth example of the method optionally includes one or more or each ofthe first through ninth examples, and further includes wherein an amountof adjustment of the duty cycle of the first motor is different than anamount of adjustment of the duty cycle of the second motor. An eleventhexample of the method optionally includes one or more or each of thefirst through tenth examples, and further includes adjusting the shifttiming of the transmission via a learning module stored in a memory ofan electronic controller of the transmission. A twelfth example of themethod optionally includes one or more or each of the first througheleventh examples, and further includes adjusting the shift timingincludes adjusting a rotation timing of the first barrel cam andadjusting a rotation timing of the second barrel cam independently ofeach other based on a predicted response rate of the first barrel camand a predicted response rate of the second barrel cam determined by theelectronic controller via the learning module. A thirteenth example ofthe method optionally includes one or more or each of the first throughtwelfth examples, and further includes wherein an input of the learningmodule is the oil temperature, and an output of the learning module isthe predicted response rate of the first barrel cam and the predictedresponse rate of the second barrel cam. A fourteenth example of themethod optionally includes one or more or each of the first throughthirteenth examples, and further includes adjusting the rotation timingof the first barrel cam includes adjusting an energization of a firstmotor configured to drive the first barrel cam based on the predictedresponse rate of the first barrel cam, and adjusting the rotation timingof the second barrel cam includes adjusting an energization of a secondmotor configured to drive the second barrel cam based on the predictedresponse rate of the second barrel cam.

In another representation, a method comprises: adjusting a shift timingof a transmission of a vehicle by controlling a rotation timing of afirst barrel cam of a shift assembly of the transmission around arotational axis via a first motor, controlling a rotation timing of asecond barrel cam of the shift assembly around the rotational axis via asecond motor, independent of the rotation timing of the first barrelcam, and adjusting the rotation timing of the first barrel cam and therotation timing of the second barrel cam based on a speed of the vehicleand a commanded torque output of the vehicle. In a first example of themethod, the method further comprises, responsive to a first condition,controlling the rotation timing of the first barrel cam to rotate onlythe first barrel cam, in a first direction, to engage a first gear in agear sequence of the transmission. A second example of the methodoptionally includes the first example, and further includes wherein thefirst condition includes transitioning the vehicle from a neutral modeto a drive mode. A third example of the method optionally includes oneor both of the first and second examples, and further includes,responsive to a second condition, controlling the rotation timing of thefirst barrel cam to rotate only the first barrel cam, in the firstdirection, to engage a second gear in the gear sequence of thetransmission. A fourth example of the method optionally includes one ormore or each of the first through third examples, and further includeswherein the second condition includes transitioning the speed of thevehicle above a second threshold speed. A fifth example of the methodoptionally includes one or more or each of the first through fourthexamples, and further includes, responsive to a third condition,controlling the rotation timing of the first barrel cam to rotate thefirst barrel cam in the first direction to disengage the second gear,while controlling the rotation timing of the second barrel cam toconcurrently rotate the second barrel cam in the first direction toinitiate engagement of a third gear in the gear sequence of thetransmission. A sixth example of the method optionally includes one ormore or each of the first through fifth examples, and further includeswherein the third condition includes transitioning the speed of thevehicle above a third threshold speed. A seventh example of the methodoptionally includes one or more or each of the first through sixthexamples, and further includes where the third threshold speed isgreater than the second threshold speed, and the second threshold speedis greater than the first threshold speed. An eighth example of themethod optionally includes one or more or each of the first throughseventh examples, and further includes, responsive to a park condition,controlling the rotation timing of the first barrel cam to rotate thefirst barrel cam to engage a first gear in a gear sequence of thetransmission, while concurrently controlling the rotation timing of thesecond barrel cam to rotate the second barrel cam to engage a third gearin the gear sequence of the transmission.

In another representation, a system comprises: a transmission; a firstbarrel cam; a second barrel cam arranged coaxially with the first barrelcam; a first motor configured to drive the first barrel cam via a firstgear assembly; a second motor configured to drive the second barrel camindependent of the first barrel cam via a second gear assembly, wherethe second gear assembly is arranged coaxially with the first gearassembly; an oil temperature sensor; and a controller with computerreadable instructions stored on non-transitory memory that whenexecuted, cause the controller to: adjust a shift timing of thetransmission via the first barrel cam and the second barrel camresponsive to an oil temperature of the transmission output by the oiltemperature sensor. In a first example of the system, the first barrelcam and second barrel cam are coupled via a protrusion of the secondbarrel cam arranged within a recess of the first barrel cam, with theprotrusion and recess each arranged along a rotational axis of the firstbarrel cam and second barrel cam, and where the first barrel cam and thesecond barrel cam are rotatable independently of each other. A secondexample of the system optionally includes the first example, and furtherincludes wherein the first barrel cam includes a first plurality ofdetents arranged along an outer perimeter of the first barrel cam at aside of the first barrel cam opposite to the recess, and the secondbarrel cam includes a second plurality of detents arranged along anouter perimeter of the second barrel cam at a side of the second barrelcam opposite to the protrusion. A third example of the system optionallyincludes one or both of the first and second examples, and furtherincludes wherein the controller further includes instructions stored onthe non-transitory memory that when executed, cause the controller to:adjust a rotation timing of the first barrel cam and adjust a rotationtiming of the second barrel cam independently of each other based on apredicted response rate of the first barrel cam and a predicted responserate of the second barrel cam determined by the controller based on theoil temperature. A fourth example of the system optionally includes oneor more or each of the first through third examples, and furtherincludes a first shift fork including a first following pin seatedwithin a first cam track of the first barrel cam, and a second shiftfork including a second following pin seated within a second cam trackof the second barrel cam, where the first shift fork is configured toslide along a first axis parallel to the rotational axis of the firstbarrel cam and the second barrel cam responsive to a rotation of thefirst barrel cam, and the second shift fork is configured to slide alongthe first axis responsive to a rotation of the second barrel cam. Afifth example of the system optionally includes one or more or each ofthe first through fourth examples, and further includes a vehicle speedsensor; and instructions stored on the non-transitory memory of thecontroller that when executed, cause the controller to: adjust a gearengagement of the transmission by controlling a rotational position ofthe first barrel cam and the second barrel cam. A sixth example of thesystem optionally includes one or more or each of the first throughfifth examples, and further includes a power source electrically coupledto the first motor and second motor; and instructions stored on thenon-transitory memory of the controller that when executed, cause thecontroller to: control the rotational position of the first barrel camby adjusting a first amount of electrical power and a first polarity ofthe electrical power provided to the first motor by the power source;and control the rotational position of the second barrel cam byadjusting a second amount of electrical power and a second polarity ofthe electrical power provided to the second motor by the power source.

In another representation, a method comprises: controlling a shifttiming of a transmission of a vehicle by controlling a rotation timingof a first barrel cam of a shift assembly of the transmission around arotational axis via a first motor and controlling a rotation timing of asecond barrel cam of the shift assembly around the rotational axis via asecond motor, independent of the rotation timing of the first barrelcam, where the rotation timing of the first barrel cam and the rotationtiming of the second barrel cam are each based on a speed of the vehicleand a commanded torque output of the vehicle. In a first example of themethod, the method further comprises: adjusting the shift timing byadjusting only the rotation timing of the first barrel cam; andresponsive to a condition, transitioning the transmission directlybetween engagement of a first gear of a gear sequence of thetransmission and engagement of a second gear of the gear sequence withthe adjusted shift timing. A second example of the method optionallyincludes the first example, and further includes wherein the conditioncomprises the speed of the vehicle transitioning above or below athreshold vehicle speed. A third example of the method optionallyincludes one or both of the first and second examples, and furtherincludes wherein the condition comprises the commanded torque output ofthe vehicle transitioning above or below a threshold commanded torqueoutput. A fourth example of the method optionally includes one or moreor each of the first through third examples, and further includeswherein adjusting the shift timing by adjusting only the rotation timingof the first barrel cam includes advancing or retarding the rotationtiming of only the first barrel cam. A fifth example of the methodoptionally includes one or more or each of the first through fourthexamples, and further includes: adjusting the shift timing byconcurrently adjusting each of the rotation timing of the first barrelcam and the rotation timing of the second barrel cam; and responsive toa condition, transitioning the transmission directly between engagementof a first gear or a second gear of a gear sequence of the transmissionand engagement of a third gear of the gear sequence with the adjustedshift timing. A sixth example of the method optionally includes one ormore or each of the first through fifth examples, and further includeswherein the condition comprises the commanded torque output of thevehicle transitioning above or below a threshold commanded torqueoutput. A seventh example of the method optionally includes one or moreor each of the first through sixth examples, and further includeswherein the condition comprises a rate of change of the commanded torqueoutput exceeding a threshold rate of change. An eighth example of themethod optionally includes one or more or each of the first throughseventh examples, and further includes wherein the condition comprises arate of change of the vehicle speed exceeding a threshold rate ofchange. A ninth example of the method optionally includes one or more oreach of the first through eighth examples, and further includes whereinadjusting the shift timing by adjusting each of the rotation timing ofthe first barrel cam and the rotation timing of the second barrel camincludes advancing each of the rotation timing of the first barrel camand the rotation timing of the second barrel cam or retarding each ofthe rotation timing of the first barrel cam and the rotation timing ofthe second barrel cam.

It will be appreciated that the configurations and routines disclosedherein are exemplary in nature, and that these specific embodiments arenot to be considered in a limiting sense, because numerous variationsare possible. As used herein, an element or step recited in the singularand proceeded with the word “a” or “an” should be understood as notexcluding plural of said elements or steps, unless such exclusion isexplicitly stated. Furthermore, references to “one embodiment” of thepresent invention are not intended to be interpreted as excluding theexistence of additional embodiments that also incorporate the recitedfeatures. Moreover, unless explicitly stated to the contrary,embodiments “comprising,” “including,” or “having” an element or aplurality of elements having a particular property may includeadditional such elements not having that property. The terms “including”and “in which” are used as the plain-language equivalents of therespective terms “comprising” and “wherein.” Moreover, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements or a particular positionalorder on their objects.

This written description uses examples to disclose the invention,including the best mode, and also to enable a person of ordinary skillin the relevant art to practice the invention, including making andusing any devices or systems and performing any incorporated methods.The patentable scope of the invention is defined by the claims, and mayinclude other examples that occur to those of ordinary skill in the art.Such other examples are intended to be within the scope of the claims ifthey have structural elements that do not differ from the literallanguage of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims.

The invention claimed is:
 1. A method, comprising: controlling arotational position of a first barrel cam of a shift assembly of atransmission around a rotational axis via a first motor; controlling arotational position of a second barrel cam of the shift assembly aroundthe rotational axis via a second motor, independent of the rotationalposition of the first barrel cam; and adjusting a shift timing of thetransmission via the first barrel cam and the second barrel camresponsive to an oil temperature of the transmission, wherein adjustingthe shift timing based on the oil temperature includes adjusting arelative rotation timing of the first barrel cam and the second barrelcam based on the oil temperature.
 2. The method of claim 1, whereinadjusting the relative rotation timing of the first barrel cam and thesecond barrel cam includes maintaining a duration between disengagementof a second gear of the transmission and engagement of a third gear ofthe transmission by retarding a rotation of the second barrel camrelative to a rotation of the first barrel cam responsive to the oiltemperature.
 3. The method of claim 1, wherein adjusting the relativerotation timing of the first barrel cam and the second barrel camincludes reducing a duration between disengagement of a second gear ofthe transmission and engagement of a third gear of the transmission byadvancing a rotation of the second barrel cam relative to a rotation ofthe first barrel cam responsive to the oil temperature.
 4. The method ofclaim 1, wherein adjusting the relative rotation timing of the firstbarrel cam and the second barrel cam includes controlling a rotationspeed of the first barrel cam based on the oil temperature bycontrolling an energization of the first motor, and controlling arotation speed of the second barrel cam based on the oil temperature bycontrolling an energization of the second motor.
 5. The method of claim4, wherein controlling the energization of the first motor includesadjusting a duty cycle of the first motor and controlling theenergization of the second motor includes adjusting a duty cycle of thesecond motor, where an amount of adjustment of the duty cycle of thefirst motor is independent of an amount of adjustment of the duty cycleof the second motor.